bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Proliferative Adipocytes, Newly Identified Adipose Progenitor, as the Precursors of Beige Cells
Authors: TAGUCHI KOICHIRO , KAJITA KAZUO , FUWA MASAYUKI , ASANO MOTOCHIKA , KITADA YOSHIHIKO , IKEDA TAKAHIDE , ISHIZUKA TATSUO , MORITA HIROYUKI
Published: June 2018

We previously identified proliferative cells in adipose tissue expressing adipocyte specific genes and preadipocyte specific genes, which were named small proliferative adipocytes (SPA). Furthermore, we found that SPA specifically express proliferin (PLF) and have superior potential for adipogenic differentiation as compared to stromal vascular cells (SVC). In this study, we investigated the role of SPA. A comparison between differentiated SPA (D-SPA) and differentiated SVC (D-SVC) revealed that UCP1 and PLF were strongly expressed in D-SPA. Therefore, we speculated that SPA might be progenitor of beige cells. The real time PCR analyses and the immunohistochemical studies revealed that beige cells associated genes, including UCP1, PPARα and PGC1α were significantly increased in D-SPA. Treatment with pioglitazone and CL316234, a specific β3-adrenergic receptor agonist, converted cultured SPA into cell clusters like beige cells which expressed UCP1 and activation of mitochondrial function confirmed by MitoRed stain. Furthermore, PLF was expressed in beige cells induced by continuous injection of CL316243.

In conclusion, since D-SPA were found to express UCP1 and PLF, which were detected in beige cells, but not WAT, SPA were considered to be a progenitor of beige cells. There might be two lineages of cells in adipose tissue; adipose progenitor cells in SVC and WAT (PLF-), and SPA and beige cells (PLF+). The combination of pioglitazone and CL316423 produced an additive effect of inducing browning in SPA.

Disclosure

K. Taguchi: None. K. Kajita: None. M. Fuwa: None. M. Asano: None. Y. Kitada: None. T. Ikeda: None. T. Ishizuka: None. H. Morita: None.
The SDF1-CXCR4 Signals Regulate Adipose Tissue Expansion by Modulating Angiogenesis in Diet-Induced Obesity in Mice
Authors: WADA TSUTOMU , WATANABE ERI , KOTERA YURI , ONOGI YASUHIRO , TSUNEKI HIROSHI , SASAOKA TOSHIYASU
Published: June 2018

Adipose tissue (AT) expands with angiogenesis in obesity. Mature vessels in the epididymal white adipose tissue (eWAT) are tightly wrapped with pericytes (PCs), which attenuates endothelial (ECs) proliferation. We found that obesity-associated increase of PDGF-B promoted detachment of PCs from nature vessels; thereby vessels were prone to neoangiogenesis. In this study, we aimed to clarify the role of stromal cell derived factor 1 (SDF1), another proangiogenic factor in the AT development in obesity. In the whole-mount immunofluorescence study of organ cultured eWAT, treatment with PDGF-B or SDF1 for 24 h significantly promoted detachment of PCs from vessels. The effect of SDF1 on PCs was reproduced by treatment with ATI2341, a potent CXCR4 agonist, but not by VUX11207, a CXCR7 agonist. Interestingly, PCs were well associated with vessels when tissue was treated with both PDGF-B and SDF1. In addition, the association was declined by preincubation with AMD3100, a CXCR4 antagonist or when AT was derived from Pdgfrb knockout mice. To further explore the in vivo effect of SDF1 in AT during obesity, we administrated Anagliptin (Ana), a DPP-4 inhibitor to C57BL/6J mice fed chow or HFD for 12 weeks, since SDF1 is a known substrate for DPP-4. The protein amount of SDF1 was significantly elevated in the eWAT of Ana-treated mice. Importantly, HFD-induced adipose tissue expansion was significantly attenuated with reduced vascular density and PCs detachment in the eWAT by Ana. To clarify the mechanism by which PCs attach even under HFD-fed condition by coexistence of SDF1 and PDGF-B, we isolated ECs, PCs, and macrophages (Mφ) from eWAT of mice. Expression of PDGFB was increased in Mφ and decreased in ECs by HFD, whereas these changes were attenuated and the gradient of PDGFB concentration between PCs and ECs was blunted in Ana-treated eWAT. These findings suggest that both PDGF-B and SDF1 coordinately regulate PCs detachments and adipose tissue expansion with obesity in mice.

Disclosure

T. Wada: Research Support; Self; Sanwa Kagaku Kenkyusho Co., Ltd.. E. Watanabe: None. Y. Kotera: None. Y. Onogi: None. H. Tsuneki: None. T. Sasaoka: None.
Interaction of Endothelial Cell Mineralocorticoid Receptor, Noncoding RNA, and Exosomes in Diet-Induced Vascular Stiffness and Insulin Resistance
Authors: JIA GUANGHONG , AROOR ANNAYYA R. , HABIBI JAVAD , WHALEY-CONNELL ADAM , SOWERS JAMES
Published: June 2018

Insulin-mediated capillary recruitment is important for increasing the vascular surface area for both insulin and glucose delivery and subsequent muscle glucose-uptake. Our recent data suggest Western diet (WD) induces vascular stiffness and impairs insulin-mediated capillary recruitment by activation of cell-specific endothelial cell (EC) mineralocorticoid receptor (MR). Here, we further hypothesized interaction of ECMR, noncoding RNA, and exosome contributes to WD-induced impairment of vascular stiffness and insulin sensitivity. Six week-old ECMR KO and littermate wild type control male mice were fed a mouse chow or WD containing excess fat (46%) and fructose (17.5%) for 16 weeks. Insulin sensitivity and vascular activity were determined by intraperitoneal glucose tolerance test and wire myograph system. ECMR KO mice prevented WD-impaired systemic insulin sensitivity and improved the aortic vasodilation responses to acetylcholine (10-9-10-4 mol/L) and insulin (0.1- 300 ng/ml), which were impaired by WD. The impairment of insulin sensitivity and vascular function was associated with abnormal expression of noncoding RNA including microRNA (miR)-7, -23, -34, -92, -429, -449, -466 as well as long noncoding RNA-kis2, -Mirt1, -Nron, -Cox2 examined by RNA sequencing, which are associated endothelium inflammation and vascular remodeling. In vitro cultured ECs, aldosterone (10-7 mol) also increased EC exosome release and miR-103 expression. Furthermore, application of a miR103 inhibitor to ECs in vitro attenuated aldosterone-induced downregulation of serine (Ser) 1177/activation of endothelial nitric oxide synthase and upregulation of intercellular adhesion molecule 1. These findings suggest that increased ECMR signaling and associated abnormal expression and release of noncoding RNA and exosome play a key role in obesity-induced vascular stiffness and insulin resistance.

Disclosure

G. Jia: None. A.R. Aroor: None. J. Habibi: None. A. Whaley-Connell: None. J. Sowers: None.
Evidence of CB1-Receptor Antagonism in Fat-Fed Dogs Promoting Beiging of Adipose Tissue Mainly via Activation of Sarco/Endoplasmic Reticulum Ca2+ ATPase 2b and Ryanodine Receptor 2
Authors: PASZKIEWICZ REBECCA L. , BERGMAN RICHARD N. , RICHEY JOYCE M. , IYER MALINI S. , WOOLCOTT ORISON O. , KOLKA CATHRYN M. , CLEGG DEBORAH , KABIR MORVARID
Published: June 2018

We have previously demonstrated that 16 weeks following exposure to a high fat diet (HFD), dogs treated with the CB1-receptor antagonist (Rimonabant (RIM)) upregulated β3-adrenergic receptors, PGC1α, Prdm16, and slight increase of UCP1 in the subcutaneous (SC) and visceral (VIS) depots when compared to control treated dogs. These data suggest an improvement in metabolic flux of adipose tissue consistent with beiging. The mechanism(s) by which RIM promotes adipose tissue beiging is unknown. We hypothesize that the beiging effect might be induced via UCP1-independent thermogenic mechanisms through upregulation of sarco/endoplasmic reticulum Ca2+-ATPase 2b (SERCA2b) and ryanodine receptor 2 (RyR2). To explore the mechanism by which RIM enhances adipose tissue function, dogs were fed a HFD (52% fat) for 6 weeks followed by a continued 16 weeks of fat feeding with either HFD + placebo (PL) (n=9) or HFD + RIM (1.25 mg/kg per day; n=11). Biopsies from SC and VIS depots were obtained for gene expression: before HFD (pre-fat) and 16 weeks of HFD +/- RIM. RIM increased SERCA2b expression in the SC depot by 8-fold (P<0.05) and in the VIS depot by 2-fold (P<0.05) compared to the PL+HFD groups. Also, RIM increased RyR2 3-fold in the SC (P<0.005) and 4-fold in the VIS depots (P<0.05). Our data suggest that a potential mechanism by which CB1-receptor antagonism increases beiging of adipose tissues may be through upregulation of the key genes involved in an UCP1-independent pathway. Importantly, for the first time we are beginning to identify mechanisms by which CB1-receptor antagonism enhances adipose tissue function and improves energy homeostasis in the presence of a HFD.

Disclosure

R.L. Paszkiewicz: None. R.N. Bergman: Advisory Panel; Self; Ingredion, Inc.. Research Support; Self; AstraZeneca. Consultant; Self; GI Dynamics Inc.. Research Support; Self; National Institute of Diabetes and Digestive and Kidney Diseases. Consultant; Self; Novo Nordisk A/S. J.M. Richey: None. M.S. Iyer: None. O.O. Woolcott: None. C.M. Kolka: Research Support; Self; AstraZeneca. D. Clegg: None. M. Kabir: None.
Gender-Dependent EPO Action in Adipose Tissue
Authors: LEE JEEYOUNG , NOGUCHI CONSTANCE T.
Published: June 2018

Erythropoietin (EPO) is a glycoprotein that stimulates the production of red blood cells. Recent studies have shown the nonerythroid effect of EPO involved in metabolic regulation. EPO treatment attenuated body weight gain in male mice on normal chow, high fat diet induced obese mice and ob/ob mice. EPO regulation of body weight is concomitant with reduction in fat mass. EPO improved glycemic control in both male and female obese mouse models. However, the metabolic response to EPO to reduce weight gain primarily via reduced fat mass appears to be gender specific. Although EPO reduced weight gain in 6 month old female mice on high fat diet, regulation of body weight was not observed in young female mice on high fat diet. In contrast, young ovariectomized female mice on high fat diet showed EPO reduction in weight gain. This sex-specific reduction in weight gain is associated with female hormones as the decreased weight gain with EPO treatment in ovariectomized female mice on high fat diet is abrogated with estrogen supplementation. To determine specific in vivo consequences of potential gender differential response of white adipose tissue with EPO treatment, we examined signal transduction in diet induced obese mice following acute EPO treatment. Analyzing white adipose tissue harvested at 0, 30 min and 60 min following single dose administration of EPO (3000 U/kg), we found that EPO activated Erk signaling in white adipose tissue of male mice. In contrast, there was no evidence of acute Erk response in white adipose tissue of female mice following EPO treatment. Erk is known for its involvement in adipocyte differentiation, adiposity, and high-fat diet induced obesity. These data suggest that estrogen is a key modifier in the metabolic response to EPO, in part via EPO regulation of Erk signaling with gender specificity. Together, these results elucidate a potential mechanism for cross talk between EPO and estrogen, and provide a novel insight about gender specific EPO action to control adipose tissue development.

Disclosure

J. Lee: None. C.T. Noguchi: None.
Siah2 in Adipocytes Promotes M2-Like Macrophage Activation in Adipose Tissue
Authors: KILROY GAIL E. , TAYLOR JESSICA L. , DANG THANH , YU YONGMEI , FLOYD ELIZABETH
Published: June 2018

Obesity is associated with chronic, low-grade adipose tissue inflammation that is linked to glucose intolerance and insulin resistance. Although enzymes of the ubiquitin-proteasome system are known to regulate signaling in classical inflammation, involvement of the ubiquitin-proteasome system in obesity-induced metabolic inflammation is relatively unexplored. We previously found that the ubiquitin ligase mammalian homolog of seven-in-absentia (Siah2) alters peroxisome proliferator-activated receptor γ (PPARγ) protein levels and selectively regulates PPARγ activity. Using a mouse model of global Siah2 deletion (Siah2KO), we observed that Siah2KO mice become obese on a high fat diet (HFD), but remain glucose tolerant and insulin sensitive. This corresponds to reduced expression of pro-inflammatory markers, substantially fewer crown-like structures and less fibrosis in adipose tissue although the adipocytes are enlarged. To determine if Siah2 expression in adipocytes accounts for the Siah2KO phenotype, we created an adipocyte-specific Siah2KO model (Siah2AdKO). Although HFD-induced obesity is attenuated in Siah2AdKO mice, the mice become glucose intolerant and insulin resistant. The visceral adipose tissue is infiltrated by M1-like macrophages, corresponding to increased crown-like structures and fibrosis while M2-like macrophages are reduced. PPARγ activity is selectively regulated, but PPARγ protein levels are unchanged in the Siah2AdKO mice. The levels of pro-inflammatory markers such as IL-6 are increased, but as in the global Siah2KO model, TNFα, SAA3 and PAI-1 expression is decreased. Thus, our data indicates Siah2 in adipocytes influences polarization of macrophages in adipose tissue independent of regulating PPARγ protein levels. Moreover, Siah2 in adipocytes mediates expression of a subset of pro-inflammatory adipokines, but surprisingly, these factors do not appear to drive adipose tissue inflammation in this model of obesity.

Disclosure

G.E. Kilroy: None. J.L. Taylor: None. T. Dang: None. Y. Yu: None. E. Floyd: None.
Liver-Specific Reactivation of MC3R Partially Reverses the Obesity of MC3R Deficiency
Authors: LEVI NOAH J. , JUN JOO YUN , PATEL TUSHAR P. , UHLMAN ANDREW J. , ROBERSON ROBIN , YANOVSKI JACK A.
Published: June 2018

The Melanocortin 3 Receptor (MC3R) regulates appetite, food intake, and energy expenditure in humans and mice. MC3R is primarily expressed in the hypothalamus and other CNS regions but is also present in peripheral tissues including the liver. Total body knockouts of MC3R have a distinct obese phenotype of increased fat mass with decreased lean mass. However, when MC3R is reactivated only in the brain of mice that are globally MC3R deficient, the obese phenotype is not completely recovered compared to wild type mice, suggesting peripheral MC3R may also regulate energy homeostasis. To begin to examine the role of peripheral MC3R in energy balance, we investigated the extent to which liver specific reactivation of MC3R reversed the obese phenotype seen in the global knockout. We generated a liver specific MC3R recovery model by crossing a floxed-transcription blocker MC3R (MC3R-/-) mouse line with mice expressing albumin-Cre recombinase (Alb-Cre+/+); both strains were in a C57BL/6J (BL/6) background. We measured the body weight and body composition (using dual energy X-ray absorptiometry) of 10-12-week-old MC3R-/-, MC3R-/- + Alb-Cre +/-, and MC3R-/- + Alb-Cre +/+ and BL/6 mice. We found amongst female mice that expression of Alb-Cre (reactivating only hepatic MC3R) was sufficient to partially reverse the increased percentage fat mass of MC3R-/- (MC3R-/-: n=15, 22.15 ± 4.78%; MC3R-/- + Alb-Cre +/- : n=5, 21.22 ± 3.13%; MC3R-/- + Alb-Cre +/+ : n=3, 17.83 ± 4.04%; BL/6: n=17, 15.72 ± 3.18%; p < 0.0001). A similar pattern of partial recovery was also observed for fat grams (p=0.0009), % lean mass (p=0.0003), and lean grams (p=0.002), with no differences in body weight amongst genotypes (p=0.612). Data for male mice were insufficient to perform analyses at this time. We conclude hepatic MC3R is an important regulator of energy homeostasis and body composition. The potential roles for MC3R in other tissues where it is expressed remain to be determined.

Disclosure

N.J. Levi: None. J. Jun: None. T.P. Patel: None. A.J. Uhlman: None. R. Roberson: None. J.A. Yanovski: Research Support; Self; Rhythm Pharmaceuticals Inc., Zafgen.
Mice Lacking Both Cannabinoid-1 and Cannabinoid-2 Receptors Are Resistant to Diet-Induced Obesity
Authors: ALSHAARAWY OMAYMA , KURJAN EMILY , TRUONG NGUYEN , OLSON LAWRENCE K.
Published: June 2018

Exogenous cannabinoids are a group of related compounds derived from the Cannabis plant, commonly known as marijuana. The discovery of cannabinoid receptors (CB1R and CB2R) has provided a platform for investigating the health effects of cannabinoids. The CB1R is predominantly expressed in the central nervous system, whereas CB2R is primarily expressed in the immune system. Mounting evidence has shown that activation of CB1 is associated with increased food intake and obesity, whereas activation of CB2 is associated with decreased levels of cytokines associated with insulin resistance and type 2 diabetes (T2D). Epidemiological studies, however, have shown a decreased prevalence of obesity and T2D among cannabis users. Here we use high-fat diet (HFD, 45% of calories from fat vs. control LFD with 10% of calories from fat) to study the metabolic changes in male mice lacking receptors of the cannabinoid system (CB-DKO) when compared to wild type (WT) C57BL/6 mice. Eight-weeks old CB-DKO mice displayed lower body fat percent and higher percent of lean mass tissue when compared to WT mice. After 12 weeks, WT mice gained an average of 22 grams on HFD compared to 9 grams on LFD. CB-DKO mice did not respond to HFD, gaining an average of 5 grams on both HFD and LFD. This corresponded to a 5% increase in body fat in CB-DKO mice compared to 18% increase in WT mice. Glucose tolerance test indicated increased insulin sensitivity in CB-DKO mice. Automated measurements revealed no significant differences in food intake or locomotion between CB-DKO and WT mice, whereas CB-DKO mice displayed higher indirect calorimetry parameters including VO2, respiratory exchange ratio, and energy expenditure. Gene expression analysis confirmed an upregulation of thermogenic genes (UCP1, CIDEA, and COX8B) suggesting browning of white adipose tissue in CB-DKO mice. These findings highlight the role of the cannabinoid system in metabolic control of adipose tissues and their potential role for insulin resistance and T2D risk.

Disclosure

O. Alshaarawy: None. E. Kurjan: None. N. Truong: None. L.K. Olson: None.
Characterization of AJ5012 as a Novel Peripheral Cannabinoid 1 Receptor Antagonist in Mouse Models of Obesity
Authors: KIM JUNGEUN , YOON JUHWAN , KIM EUNHA , YOON SUNG-HWA , KIM WOOK
Published: June 2018

Obesity-induced adipose tissue inflammation, in which the NLRP3 inflammasome is a pivotal mediator, is implicated in the development of insulin resistance. Cannabinoid 1 receptor (CB1R) antagonists have been shown to improve insulin resistance and the associated metabolic abnormalities, but their therapeutic development was discontinued due to neuropsychiatric side effects. Although growing evidence suggests the role of CB1Rs in proinflammatory signaling, their direct effects on adipose tissue inflammation have not yet been evaluated. Here we report that the peripherally restricted CB1R antagonist AJ5012, which exhibits beneficial metabolic effects comparable with its brain-penetrant parent compound rimonabant, suppresses macrophage infiltration into white adipose tissue, activation of the NLRP3 inflammasome, and production of proinflammatory cytokines in diet-induced obese mice. Moreover, we identified the downstream signaling pathways by which CB1R regulates proinflammatory gene expression. These results suggest that peripheral CB1R blockade improves obesity-induced insulin resistance by suppressing adipose tissue inflammation via the NLRP3 inflammasome.

Disclosure

J. Kim: None. J. Yoon: None. E. Kim: None. S. Yoon: None. W. Kim: None.
Adaptation Process of the Transposed Ileum during Early Postoperative Period after Ileal Transposition
Authors: AHN CHANG HO , OH TAE JUNG , MOON SUN JOON , KWAK SOO HEON , PARK KYONG SOO , CHO YOUNG MIN
Published: June 2018

The intestine undergoes diverse changes to adapt the altered environment after bariatric surgery, which have various implications in the molecular mechanisms of bariatric surgery. Ileal transposition (IT) is an experimental surgery to investigate the role of the distal ileum in bariatric surgeries. To systematically investigate the gut adaptation process in IT, we performed a gene expression profiling of the transposed ileum compared to the ileum in situ at different postoperative time points. Sprague-Dawley rats fed a chow diet underwent IT or sham surgery. In IT, 10 cm of the distal ileal segment was transposed distal to the Treitz ligament. In sham surgery, the intestine was resected at the same anatomical location and anastomosed in situ. Either 1 or 4 weeks after surgery, total RNA was extracted from the ileal tissue and used for microarray analysis. Principal component analysis showed that the difference between 1 and 4 weeks was the largest. The difference between IT and sham groups were larger at 4 weeks than 1 week. A total of 1792 differentially expressed genes (DEGs) were identified including 659 and 1133 DEGs at 1 and 4 weeks, respectively. Interestingly, only 45 and 24 DEGs were commonly up- or down-regulated at the two time points, remaining 96.1% of DEGs were uniquely regulated at either time points. The network analysis showed that the affected biologic processes were related to structural (cell adhesion and immune responses) and functional (glucose and fatty acid metabolism) adaptations. Up-regulated extracellular proteins and their interacting integrins at 1 week, and cytokines, chemokines and their receptors at 4 weeks were interlinked. In glucose metabolism, up-regulation of GLUT2, HK3 and down-regulation of G6PC suggested enhanced glucose uptake and glycolysis. Collectively, our results suggest that the adaptation process of the transposed ileum dynamically evolve during early postoperative period incorporating structural and functional changes.

Disclosure

C. Ahn: None. T. Oh: None. S. Moon: None. S. Kwak: None. K. Park: None. Y. Cho: None.
Genetic Nicotinamide N-Methyltransferase Deficiency Improves Insulin Sensitivity in DIO Mice
Authors: BRACHS SEBASTIAN , POLACK JAMES , BRACHS MARIA , JAHN-HOFMANN KERSTIN , ELVERT RALF , PFENNINGER ANJA , BÄRENZ FELIX , MARGERIE DANIEL , MAI KNUT , KANNT AIMO , SPRANGER JOACHIM
Published: June 2018

Nicotinamide N-methyltransferase (NNMT) is expressed in most tissues including muscle, adipose tissue, liver and digestive organs. Recent research suggests the involvement of NNMT in the pathogenesis of obesity, insulin resistance and related metabolic disease. Antisense oligonucleotide (ASO) knockdown in high-fat diet (HFD)-fed mice led to reduced weight gain, relative fat mass, plasma insulin levels and improved glucose tolerance. We tested the hypothesis, that genetic NNMT deletion protects mice on HFD and Western diet (WD) against obesity and explored the metabolic effects of NNMT. Using NNMT ASO treatment and a NNMT knockout mouse (NNMT-/-), we investigate the effects of NNMT deletion on energy metabolism, glucose homeostasis and the development of obesity. We also examined data from a human study concerning NNMT expression and 1-methylnicotinamide (MNA) levels regarding weight reduction. In WD-fed mice, NNMT ASO treatment improved acute glucose tolerance, reduced weight gain and fat mass increase and, consequently, lowered plasma insulin levels. NNMT-/- mice exhibited virtually no MNA but threefold higher nicotinamide levels. Whereas NNMT-/- male and female mice on normal chow revealed no metabolic phenotype, NNMT-/- males on HFD showed improved glucose infusion rates, nearly complete insulin-mediated suppression of endogenous glucose production and an enhanced glucose uptake during a hyperinsulinemic-euglycemic clamp. Furthermore, NNMT-/- females on WD showed reduced weight gain, less fat mass and lower plasma insulin levels compared to controls. While NNMT gene expression in human fat biopsies increased over weight loss, corresponding plasma MNA levels significantly declined after weight reduction, suggesting that other mechanisms rather than adipose NNMT expression modulate circulating MNA levels during weight reduction.

In conclusion, we observed an improvement of basal metabolic parameters and insulin sensitivity in NNMT-deficient mouse models.

Disclosure

S. Brachs: Research Support; Self; Sanofi-Aventis Deutschland GmbH. J. Polack: None. M. Brachs: Research Support; Spouse/Partner; Sanofi. K. Jahn-Hofmann: None. R. Elvert: Employee; Self; Sanofi. A. Pfenninger: None. F. Bärenz: None. D. Margerie: Employee; Self; Sanofi-Aventis Deutschland GmbH. K. Mai: None. A. Kannt: Employee; Self; Sanofi. Stock/Shareholder; Self; Sanofi. J. Spranger: Research Support; Self; Sanofi R&D.
STAT1 Ablation in CD11c+ Cells Protects Mice from Obesity-Induced Insulin Resistance
Authors: ANTONY ANTU KALATHOOKUNNEL , PERRARD XIAOYUAN D. , LIAN ZEQIN , PERRARD JERRY , HENNIGHAUSEN LOTHAR , SMITH CLIFTON W. , BALLANTYNE CHRISTIE M. , WU HUAIZHU
Published: June 2018

Background: Obesity is a global epidemic and major risk factor for insulin resistance and type 2 diabetes. Obesity is associated with low grade chronic inflammation of adipose tissue (AT). F4/80+CD11c+ macrophages/dendritic cells are increased and polarized into M1-like phenotypes in AT and may contribute to insulin resistance in mouse models of obesity. STAT1 is a transcription factor that play key roles in macrophage polarization into M1-like phenotypes. Hence, we investigated the role of CD11c+ macrophage/dendritic cell STAT1 in obesity-induced AT inflammation and insulin resistance.

Methods: Mice with specific knockout of STAT1 in CD11c+ cells were generated by crossbreeding STAT1 fl/fl and CD11c-Cre mice. CD11c/STAT1 KO and littermate controls were fed either high fat diet (HFD, for 16 weeks) to induce obesity or normal diet (ND) as lean controls. We evaluated body composition, insulin sensitivity, gene expression of inflammatory markers, various immune cells and brown/beige adipogenesis markers in AT.

Results: Perigonadal white AT (PWAT) and body weight were not significantly different between KO and control groups but liver weight and liver-to-body weight ratio were significantly reduced in obese KO mice (p<0.05). STAT1 KO mice on HFD exhibited improved insulin sensitivity examined by insulin tolerance test (p<0.05) and reduced expression of inflammatory markers TNFα, IFNγ, IL-12 and MCP1 in PWAT and subcutaneous AT (SAT) compared to littermate controls (p<0.05). AT immune cell analysis revealed that STAT1 ablation caused a decrease in M1-like proinflammatory polarization and increase in M2-like polarization of F4/80+ macrophages, reduced number of total CD3+ T cells and CD8+T cells in PWAT. In addition, brown/beige adipogenesis markers UCP1, CIDEA and Prdm16 also upregulated (p<0.05) in SAT of obese KO mice.

Conclusion: Our results show the critical role of macrophage/dendritic cell STAT1 in obesity-induced AT inflammation and insulin resistance.

Disclosure

A. Kalathookunnel Antony: None. X.D. Perrard: None. Z. Lian: None. J. Perrard: None. L. Hennighausen: None. C.W. Smith: None. C.M. Ballantyne: Research Support; Self; Abbott, Amarin Corporation, Amgen Inc., Esperion Therapeutics, Ionis Pharmaceuticals, Inc., Novartis Pharmaceuticals Corporation, Pfizer Inc., Regeneron Pharmaceuticals, Inc., Roche Diagnostics Corporation, Sanofi. Consultant; Self; Abbott, Amarin Corporation, Amgen Inc., AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Esperion Therapeutics, Ionis Pharmaceuticals, Inc., Matinas BioPharma, Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Pfizer Inc., Regeneron Pharmaceuticals, Inc., Roche Diagnostics Corporation, Sanofi. H. Wu: None.
Challenging the Adipocyte Color Barrier—TR Activation Elicits White to Beige Transdifferentiation Independent of Beta-Adrenergic Signaling
Authors: XIA YAN , LIANG XIAOFEI , LEE MARK E. , PHILLIPS KEVIN
Published: June 2018

Induction of beige adipocytes, or brown-like adipocytes, in white adipose tissues (WAT) has become an alluring possibility to combat diabetes and metabolic diseases. Beige adipocytes express abundant UCP1 protein and exert energy dissipating and thermogenic functions similar to brown adipocytes. In this study, we compared the beiging effects of a synthetic thyroid hormone receptor (TR) agonist, GC1, with the beta-adrenergic receptor (β-AR) agonist CL316243, which is generally accepted as the most efficacious beiging agent, and explored mechanistic similarities and distinctions between the two compounds in a variety of in vitro cell models.

Here we show that GC1 induces beiging, in cultured adipocytes derived from inguinal WAT, to a much greater extent than CL316243; in addition, TR activation by GC1 is sufficient to induce beiging in a variety of viscerally derived white adipocytes, as well as 3T3-L1 cells, actions which CL316243 is incapable of. Both GC1 and CL316243 increased expression of ATGL and p-HSL, two key lipases known to be necessary for the activation of UCP1-mediated uncoupling and thermogenesis, although GC1 increased these proteins to a higher extent. Enzymes involved in lipid beta-oxidation, such as ACC/p-ACC and LCAD, are also much more markedly enhanced in GC1-treated cells than those treated with CL316243. Interestingly, the loss of all β-ARs, does not affect the ability of TR activation to elicit beiging, demonstrating that TR agonism induces beiging by novel mechanisms that are independent of beta-adrenergic signaling. Thus, select TR agonists appear to be sufficient to elicit beiging in a fashion that appears to be mechanistically distinct from perhaps all other known beiging agents (nearly all of which require β-AR signaling), making them important tools in assessing the therapeutic potential of beige fat activation to treat diabetes and metabolic disease.

Disclosure

Y. Xia: None. X. Liang: None. M.E. Lee: None. K. Phillips: None.
Resistin Is Associated with Blood-Brain Barrier Disruption in Mice Resistant to Diet-Induced Obesity and Treated with Topiramate
Authors: SALAMEH THERESE S. , MORTELL WILLIAM , BANKS WILLIAM A.
Published: June 2018

Resistin has been linked to diabetes, obesity, insulin resistance, atherosclerosis, and the development of cardiovascular disease. However, the effects and the molecular mechanisms of resistin on endothelial permeability, a key event in the development of atherosclerosis, inflammation, and vascular disease, have not been fully elucidated. Diabetes is associated with changes in the brain microvasculature leading to dysfunction and disruption of the blood-brain barrier (BBB), a specialized system of microvascular endothelial cells protecting the brain from toxic substances in circulation, while permitting CNS entry of nutrients and endocrine signals using active transport mechanisms and passive diffusion. As diabetes is associated with cognitive impairment, understanding the molecular mechanisms of endothelial permeability in the brain is important in developing appropriate therapeutic agents. Topiramate (TPM), a mitochondrial carbonic anhydrase inhibitor, prevents BBB disruption in mouse models of type I and II diabetes. Mice resistant to the development of diet-induced obesity, when treated with TPM, had increased serum levels of resistin and increased BBB permeability to all brain regions except the hippocampus and hypothalamus, brain regions paradoxically disrupted in models of type II diabetes. In vitro treatment of brain endothelial cells with resistin demonstrated a decrease in endothelial nitric oxide synthase (eNOS) along with increased permeability and decreased TEER, a measure of electrical resistance across a cell monolayer. This increase in permeability occurs because diet-resistant mice treated with TPM are unable to attenuate the effects of hyperglycemia-induced oxidative stress and inflammation. Topiramate, which is protective of the BBB in types I and II diabetes, seems paradoxically toxic to the BBB in mice resistant to diet-induced obesity and this toxicity is associated with increases in serum resistin.

Disclosure

T.S. Salameh: None. W. Mortell: None. W.A. Banks: None.
Insulin Resistance and In Vivo Lipolytic Rate Are Positively Associated with Body Iron Stores in Obese Women
Authors: RYAN BENJAMIN J. , VAN PELT DOUGLAS W. , GUTH LISA M. , LUDZKI ALISON , GIOSCIA-RYAN RACHEL A. , AHN CHIWOON , HOROWITZ JEFFREY F.
Published: June 2018

High body iron stores are positively related to insulin resistance in humans, but the underlying mechanisms remain unresolved. Iron stimulates lipolysis in murine adipocytes in vitro, but the influence of iron stores on lipolytic rate in vivo is unknown. Our aim was to determine if body iron stores are associated with lipolytic rate and whole-body insulin sensitivity in obese, pre-menopausal women. We studied 20 subjects with clinically-normal (20-200 ng/mL) plasma [ferritin], an index of body iron stores. Fatty acid rate of appearance into systemic circulation (FA Ra) was assessed by 13C-palmitate isotope dilution, insulin resistance was assessed by hyperinsulinemic-euglycemic clamp, and abdominal subcutaneous adipose tissue protein expression was assessed via immunoblot. [Ferritin] was significantly (p < 0.01), positively correlated with FA Ra (r2 = 0.42), adipose hormone sensitive lipaseser660 phosphorylation (p-HSLser660, a marker of lipolytic activation in adipose tissue; r2 = 0.41), and whole-body insulin resistance (r2 = 0.33). Importantly, [ferritin] remained a significant, independent predictor for these parameters in multiple regression models including body mass index, plasma [adiponectin], and plasma [CRP] as covariates. We stratified subjects into tertiles based on [ferritin] to compare high-normal and low-normal [ferritin] groups (138 ± 30 vs. 40 ± 15 ng/mL). Compared with the low-normal [ferritin] group, the high-normal [ferritin] group had significantly (p < 0.02) higher FA Ra (15.6 ± 5.5 vs. 8.8 ± 2.4 µmol/kg fat mass/min), adipose p-HSLser660 (1.3 ± 0.4 vs. 0.6 ± 0.2 AU) and whole-body insulin resistance (glucose infusion rate 9.2 ± 2.3 vs. 14.3 ± 3.5 mg/kg fat free mass/min). There were no between-group differences in anthropometric characteristics, plasma [adiponectin], or plasma [CRP]. Our findings suggest that iron-mediated activation of adipose lipolysis may be a mechanism linking body iron stores and insulin resistance in obese humans.

Disclosure

B.J. Ryan: None. D.W. Van Pelt: None. L.M. Guth: None. A. Ludzki: None. R.A. Gioscia-Ryan: None. C. Ahn: None. J.F. Horowitz: None.
Establishing Cost-Effectiveness of "Acceptable" T1D Care in Less-Resourced Countries
Authors: OGLE GRAHAM D. , GUO JINGCHUAN , AHMADOV GUNDUZ A. , FAWWAD ASHER , GREGORY GABRIEL A. , KLATMAN EMMA L. , ORCHARD TREVOR J.
Published: June 2018

Aim: Cost-effective arguments are needed to help convince less-resourced governments to provide essential T1D services. We developed two scenarios - for Pakistan (Lower-Middle Income) (S1) and Azerbaijan (Upper-Middle Income) (S2).

Methods: We modelled the complications/costs/mortality/Disability Adjusted Life Years (DALYs) associated with achieving a mean HbA1c of 9.0% (75 mmol/mol) for S1 and 8.5% (69 mmol/mol) for S2 compared with those with a mean HbA1c level of 12.5% (113 mmol/mol). ’Acceptable care’ S1 involved human insulin by multiple daily injections (MDI), two blood glucose tests/day, education and complications screening etc. S2 was S1 with analog rather than human insulin and four tests/day. ’Minimal care’ was non-MDI insulin, syringes and routine clinic reviews. A discrete time Markov illness-death model with diabetes-duration-dependent transition probabilities was developed in R 3.3.1. Input parameters included 30 years (y) of University of Pittsburgh Epidemiology of Diabetes Complications (EDC) cohort statistics for T1D diagnosed <17 y of age and DALYs and background mortality data from WHO. Eleven complications were included. Costs were determined from international and local estimations.

Results: Complications were markedly raised with HbA1c at 12.5% compared to 9.0% and 8.5%. For instance, blindness at 30y was 49.4%, 11.6% and 9.5% respectively. For S1, 30y total costs (maintenance and cost of acute and chronic complications) were $20,919/patient at 9.0% and $20,796 at 12.5%. For S2, costs were $61,429 at 8.5% and $60,826 at 12.5%. Thirty y survival rate for Pakistan was 87% at 9.0% and 64% at 12.5%, and for Azerbaijan 91% at 8.5% and 66% at 12.5%. Cumulative DALYs lost in 30 years in Pakistan were 2.6y at 9.0% and 6.0y (12.5%). Azerbaijan was 2.0y (8.5%) and 5.8y (12.5%).

Conclusion: ’Acceptable care’ is of similar cost to ’Minimal care’ in Pakistan and Azerbaijan, with improved survival and reduced DALYs. This model can be used in other less-resourced countries.

Disclosure

G.D. Ogle: None. J. Guo: None. G.A. Ahmadov: None. A. Fawwad: None. G.A. Gregory: None. E.L. Klatman: None. T.J. Orchard: None.
Visceral and Ectopic Fat Expansion and the Risk of Incident Type 2 Diabetes Mellitus
Authors: NEELAND IAN J. , AYERS COLBY , PATEL KERSHAW V. , JOSHI PARAG H. , MCGUIRE DARREN K. , GRUNDY SCOTT M. , ROHATGI ANAND , VEGA GLORIA L.
Published: June 2018

Background: Excess visceral adipose tissue (VAT) is associated with an increased risk of prediabetes and type 2 diabetes (T2D) independent of body mass index (BMI). Whether expansion of VAT or other fat depots is associated with diabetes risk independent of weight gain is not fully known.

Methods: Among participants without prevalent diabetes or cardiovascular disease enrolled in the Dallas Heart Study, we measured body fat distribution by dual energy x-ray absorptiometry and biomarkers of glycemia at baseline (2000-2002) and repeated 7 years later. The incidence of prediabetes and T2D per ADA definitions were assessed at follow-up.

Results: The study included 1661 participants (mean age 44, 58% women, 45% black, 39% obese) with median weight gain of 3.0 (-1.1 to 7.2) kg. Eight percent of participants developed T2D and, among those with normal fasting glucose at baseline (n=1551), 36% developed prediabetes or T2D. Changes in fat depots are shown in the Table. VAT and SAT gain were associated with incident T2D and with prediabetes or T2D independent of traditional risk factors, baseline BMI, change in BMI, and baseline fat depot (Table). Increasing lower body fat was not associated with incident diabetes.

Conclusions: Expansion of VAT and SAT are both associated with incident T2D independent of weight gain. Abdominal adiposity may be a modifiable target for diabetes prevention even in the absence of generalized weight loss.

Disclosure

I.J. Neeland: Speaker's Bureau; Self; Boehringer Ingelheim GmbH. Research Support; Self; Novo Nordisk A/S, National Institute of Diabetes and Digestive and Kidney Diseases. Advisory Panel; Self; Advanced MR Analytics AB. C. Ayers: None. K.V. Patel: None. P.H. Joshi: Consultant; Self; Regeneron Pharmaceuticals, Inc. D.K. McGuire: Consultant; Self; AstraZeneca, Sanofi-Aventis, Eli Lilly and Company, Boehringer Ingelheim Pharmaceuticals, Inc., Merck & Co., Inc., Pfizer Inc., Novo Nordisk A/S. Research Support; Self; AstraZeneca, Sanofi-Aventis, Janssen Pharmaceuticals, Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk A/S, Lexicon Pharmaceuticals, Inc., Eisai Inc., GlaxoSmithKline plc., Esperion Therapeutics. S.M. Grundy: None. A. Rohatgi: Research Support; Self; Merck Sharp & Dohme Corp., American Heart Association. Consultant; Self; CSL Behring. Research Support; Self; National Heart, Lung, and Blood Institute. G.L. Vega: None.
Lipid Accumulation Product and Sarcopenia in Korean Patients with Type 2 Diabetes
Authors: SHIN JANG YEL
Published: June 2018

Lipid accumulation product (LAP), a new biomarker for lipid over accumulation in adults. has been suggested to show better relationships with insulin resistance (IR), metabolic syndrome (MS), and type 2 diabetes, and cardiovascular disease (CVD) than body mass index (BMI). Sarcopenia is proposed to risk factor for IR, MS, type 2 diabetes, and CVD. However, association between LAP and sarcopenia is not approved yet. We evaluated relationship between LAP and sarcopenia in patients with type 2 diabetes. Total of 481 subjects with type 2 diabetes were enrolled. LAP was estimated as follows: [waist circumference (WC)-65] X [triglycerides (TG)] in men and [WC-58] X [TG] in women. Appendicular skeletal muscle mass (ASM) was measured using dual energy X-ray absorptiometry (DEXA). Sarcopenia was defined as follows: ASM/ BMI<0.789 in men and <0.521 in women. Patients with the highest tertile of LAP were more likely to be hypertensive and current drinkers and less likely to have regular exercise than those with the lowest. They had higher values of BMI, systolic and diastolic blood pressure (BP), total cholesterol, HOMA-IR, and liver enzymes and lower values of age, HDL, and vitamin D3 (vitD3). Sarcopenic subjects gradually increased with increasing tertiles of LAP (p<0.05). Odds ratios (ORs) in the highest tertile of LAP for sarcopenia after adjusted for age and gender were 1.884 (95% CI=1.128-3.146, p=0.015) in 2nd tertiles and 2.784 (95% CI=1.641-4.724, p<0.001) in the highest. The association between LAP and sarcopenia remained significant after further adjustments for hypertension, currents drinking, regular exercise, total cholesterol, HDL, HOMA-IR, CRP, vitD3, and liver enzymes. LAP was significantly associated with sarcopenia in patients with type 2 diabetes independent of age, gender, hypertension, current drinking, regular exercise, BP, total cholesterol, HDL, HOMA-IR, CRP, vitD3, and liver enzymes. Further studies are required to investigate a causal relationship between LAP and sarcopenia.

Disclosure

J. Shin: None.
A Systems Approach to ER Stress Pathway Dynamics Reveals the Impact of Freeze-Dried Broccoli Extract to Mitigate Inflammation in Human Adipocytes through the Mevalonate Pathway
Authors: MURPHY ALICE , AZHARIAN SAHAR , TRIPATHI GYANENDRA , BARKER GUY , CHAPPELL MICHAEL J. , MCTERNAN PHILIP G.
Published: June 2018

Background: Delivery of nutrient excess in obesity causes endoplasmic reticulum (ER) stress within adipose tissue; this activates the unfolded protein response (UPR) and contributes to type 2 diabetes mellitus (T2DM) risk. This study aimed to utilise freeze-dried broccoli extract (BE) as a nutrient to mitigate such cellular damage in human adipocytes, and create a mathematical model to understand pathway dynamics.

Methods: Differentiated human adipocytes (Chub-S7; n=6) were treated with BE (10ng/ml) alone or combined with tunicamycin (Tun; 750ng/ml), an inducer of ER stress. UPR proteins (BiP, PERK, P-PERK, eIF2α, P-eIF2α) were measured (18 time points; 0hr-72hr) using Western Blot and transcriptomics. Mass action kinetics was used to create ordinary differential equations (ODEs) to model the UPR for predictive analysis.

Results: Tun increased UPR proteins 9.5 fold (P<0.05), whilst BE+Tun reduced ER stress proteins by 94% (P<0.05). Transcriptomic analysis highlighted significant changes in the mevalonate pathway with BE (P<0.05), whilst time series data identified oscillatory behaviour of UPR proteins. Finally, modelling pathway dynamics, time-series analysis improved the error between model output and experimental data by 23%, yielding a new enhanced qualitative model.

Conclusion: BE acts to alleviate ER stress in human adipocytes by reducing the UPR through the mevalonate pathway. Furthermore, modelling pathway dynamics using experimental data may provide insight into predicting nutrient capabilities to reduce inflammation.

Disclosure

A. Murphy: None. S. Azharian: None. G. Tripathi: None. G. Barker: None. M.J. Chappell: None. P.G. McTernan: None.
Altered Brain Resting-State Functional Connectivity in Obese Patients Is Associated with Plasma Levels of Leptin
Authors: DEVOTO FRANCANTONIO , FERRULLI ANNA , ZAPPAROLI LAURA , BONANDRINI ROLANDO , SCONFIENZA LUCA MARIA , BANFI GIUSEPPE , LUZI LIVIO , PAULESU ERALDO
Published: June 2018

There is growing evidence for the role of the insular cortex in various types of cravings, including food craving. Here, we used resting-state functional brain connectivity (FBC) to explore system-level dysfunctions in the brain of obese (OB) individuals and their correlations with the leptin levels. We first used hierarchical clustering to identify the brain regions whose altered functioning was consistently reported by neuroimaging studies on food perception in OB subjects. We found that a cluster centred in left anterior insula and overlying frontal operculum (AI/fO) was specifically associated with hyper-responsivity in OB. This cluster was then used as a seed for a seed-based FBC analysis in 10 OB and 11 normal weight controls matched for sex, age and education. The analysis implied the calculation of the functional correlations of each brain voxel with the seed along the resting state fMRI time series. OB patients, compared to the control group, showed hyper-connectivity between the left AI/fO and key regions of the reward system, such as the left medial orbitofrontal cortex (OFC), in addition to the bilateral parahippocampal gyri and the posterior cingulate gyrus; conversely, they exhibited hypo-connectivity between the seed and the left dorsolateral prefrontal cortex, a key region involved in inhibitory control (all Ps < .corrected for multiple comparisons). Finally, we found a substantial trend for a negative correlation between AI/fO-OFC hyper-connectivity and plasma levels of leptin (ρ = - .612, p = .06). Our results provide evidence for an imbalance between reward and inhibitory control systems in OB patients, which might be worsened by an altered response to food intake regulatory hormones (e.g., anorexigenic leptin), thus driving the overeating behavior. Moreover, our results suggest that the left AI could be a suitable target for drugs or neuro-modulatory treatment to recalibrate the FBC of a network involved in food intake, reward and cognitive control.

Disclosure

F. Devoto: None. A. Ferrulli: None. L. Zapparoli: None. R. Bonandrini: None. L. Sconfienza: None. G. Banfi: None. L. Luzi: Speaker's Bureau; Self; A. Menarini Diagnostics, AstraZeneca, Eli Lilly and Company. Research Support; Self; Gelesis. Consultant; Self; McKinsey & Company. Speaker's Bureau; Self; Menarini Group, Merck Sharp & Dohme Corp.. Research Support; Self; Novartis AG. Speaker's Bureau; Self; Novo Nordisk A/S. Research Support; Self; Sunstar Foundation. Speaker's Bureau; Self; Smith & Nephew. E. Paulesu: None.