bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of ChREBPa and ChREBPß in Pancreatic ß Cells
Authors: KATZ LIORA S. , LAXMAN ANIL K. , ZHANG PILI , SCOTT DONALD 
Published: June 2018

Glucose is a key physiological driver of adaptive β-cell mass expansion, promoting β-cell proliferation both in vitro and in vivo. Carbohydrate response element binding protein (ChREBP) is required for glucose-stimulated β-cell proliferation in both rodent and human β-cells. ChREBP has two splice isoforms - α and β. Translation of the ChREBPβ mRNA generates a truncated protein, resulting in a potent, constitutively active isoform. To study the role of the 2 splice isoforms in β-cell biology, we performed numerous experiments including immunostaining and chromatin immunoprecipitation with antibodies that recognize only ChREBPα or both isoforms. We found that ChREBPα is only transiently expressed in the nucleus. By contrast, ChREBPβ, once expressed at high enough levels to detect, is constitutively nuclear. Our data indicate that mice fed on high fat diet and diabetic db/db mice have abundant ChREBPβ localized in the nucleus while control mice have mostly cytoplasmic ChREBPα. We generated Ins-1 cell lines where we can distinguish between the splice isoforms using CRISPR/Cas9: 1. The C-terminus of ChREBPα and ChREBPβ was labeled with eGFP; 2. The N-terminus of ChREBPα was labeled by mCherry; and 3. ChREBPα was labeled with mCherry and eGFP on the N- and C- terminus, respectively and ChREBPβ is labeled with eGFP on the C-terminus. We validated the three cell lines by sequencing, ChIP, qRT-PCR and also showed that the glucose response is not altered in these cells. We found that in low glucose, ChREBPβ is present at very low levels in the nucleus. By contrast, in high glucose, ChREBPβ is present at high levels in the nucleus. Our study suggests that in response to glucose, ChREBPα, which is mostly cytoplasmic, transiently enters the nucleus, binds to a carbohydrate response element (ChoRE), and induces ChREBPβ expression, which is mostly nuclear. We propose that while the induction of ChREBPβ drives adaptive beta cell expansion, ChREBPβ contributes to glucose toxicity after prolonged exposure to high glucose and in diabetes.

Disclosure
L.S. Katz: None. A.K. Laxman: None. P. Zhang: None. D. Scott: None.
Diabetes and High-Fat Diet Induce Different Pathologies in Mouse Skeletal Muscle Extracellular Matrix
Authors: MARTINEZ-HUENCHULLAN SERGIO F. , BAN LINDA A. , TAO ANH , SUTANTO SURYA S. , TAM CHARMAINE , MCLENNAN SUSAN , TWIGG STEPHEN M. 
Published: June 2018

Whether obesity and diabetes (DM) similarly affect composition and function of skeletal muscle extracellular matrix (ECM) has not been resolved. This study examines the effects of long term high fat diet (HFD) and DM on rodent skeletal muscle ECM were addressed. Five week old C57BL/6 male mice were randomly allocated to standard chow (control; n=26) or HFD (45% kcal fat; n=25). After 15 weeks chow and HFD mice were rendered diabetic (by low dose STZ, 65mg/kgx3d, I.P.) (DM, n=14; HFD+DM, n=14); nondiabetic mice acted as controls. Mice were euthanased after 30 weeks and plasma and quadriceps muscle were collected for analysis. Body weight and plasma insulin expectedly decreased with DM induction and increased with HFD (all p&lt;0.05). High glucose occurred only in DM mice (∼14 mM; p&lt;0.05), whereas only HFD increased muscle triglyceride (p&lt;0.05). Both conditions induced a decrease in quadriceps weight and in grip strength performance (p&lt;0.05). Quadriceps of DM mice showed increased CTGF/CCN2 (1.5-fold; p&lt;0.05), TIMP-1 (2-fold; p&lt;0.05), collagen-I (3-fold; p&lt;0.05), -IV (2-fold; p&lt;0.05), and -VI (2-fold; p&lt;0.05) protein. In contrast, HFD induced a downregulation of CTGF/CCN2 (0.6-fold; p&lt;0.05), MMP-1 (0.6-fold; p&lt;0.05), and TIMP-2 (0.4-fold; p&lt;0.05). In DM mice quadriceps centralized nuclei (p&lt;0.05) and caspase 3 (protein; 1.5-fold; p&lt;0.05) were increased, whereas caspase 3 was decreased in HFD (0.5-fold; p&lt;0.05). Moreover, HFD induced a downregulation of ubiquitin ligase atrogin-1 protein (0.5-fold; p&lt;0.05) and mRNA levels of serine/threonine kinase p70S6k (0.75-fold; p&lt;0.05). Notably, no greater dysregulation of the muscle changes observed with DM alone or with HFD alone, was seen in HFD+DM mice. These data suggest that DM and HFD differentially affect skeletal muscle ECM: DM promotes a pro-fibrotic profile with signs of muscle damage, and HFD impairs regulatory protein turnover pathways, each inducing muscle dysfunction.

Disclosure
S.F. Martinez-Huenchullan: None. L.A. Ban: None. A. Tao: None. S.S. Sutanto: None. C. Tam: None. S. McLennan: None. S.M. Twigg: Advisory Panel; Self; Abbott. Consultant; Self; Abbott. Advisory Panel; Self; Novo Nordisk Inc., Sanofi-Aventis, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company. Speaker's Bureau; Self; AstraZeneca, Merck Sharp & Dohme Corp.. Other Relationship; Self; Abbott.
Skeletal Muscle Dysfunction and Metabolic Abnormalities in Individuals with Familial Partial Lipodystrophy Is Associated with Diminished Mitochondrial Fatty Acid Oxidation
Authors: SIMHA VINAYA , LANZA IAN R. , LEBRASSEUR NATHAN , KLAUS KATHERINE , PORT JOHN , LAURENTI MARCELLO C. , COBELLI CLAUDIO , SREEKUMARAN NAIR K. 
Published: June 2018

Background: Familial Partial Lipodystrophy, Dunnigan variety (FPLD) is characterized by post-natal fat loss leading to severe insulin resistance. Affected individuals also display striking skeletal muscle hypertrophy, but there is limited information on muscle function and energy metabolism. We therefore systematically investigated muscle and mitochondrial function in 6 individuals with FPLD and 6 matched controls.
Methods: Body composition and intramyocellular lipid content (IMCL) were assessed by DEXA and magnetic resonance spectroscopy, respectively. Maximal voluntary strength and fatigue were assessed for both recumbent leg press and seated chest press. Vastus lateralis muscle biopsies were obtained prior to and following a high fat (40%) mixed-meal. Oxygen consumption in isolated mitochondria was measured using substrates supporting carbohydrate or lipid-based respiration. Insulin Sensitivity Index (SI) was calculated by minimal modelling.
Results: Individuals with FPLD had significantly lower SI, lower body fat content, and higher lean mass. Peak leg press and chest press force were not different, but FPLD individuals had earlier fatigue during chest press (number of repetitions: 15 ± 0.6 vs. 20 ± 0.3, p = 0.01). They also had a 50-60% decrease in state 3 respiration measured using substrates supporting lipid-based respiration (p = 0.04). Further, mitochondrial oxidative capacity showed a strong correlation with muscle fatigue (r = 0.76, p = 0.003), and inversely correlated with fasting and post-prandial lipemia and measures of insulin resistance.
Conclusion: Individuals with FPLD have higher lean body mass and lower insulin sensitivity. Despite preserved peak muscle strength, they demonstrated earlier muscle fatigue. Decreased mitochondrial fatty acid oxidative capacity, likely related to elevated IMCL, may contribute to muscular and metabolic abnormalities.

Disclosure
V. Simha: None. I.R. Lanza: None. N. LeBrasseur: None. K. Klaus: None. J. Port: None. M.C. Laurenti: Other Relationship; Self; GlySens Incorporated. C. Cobelli: Research Support; Self; Sanofi-Aventis. Advisory Panel; Self; Novo Nordisk Inc.. K. Nair: None.
Skeletal Muscle Lipid Composition Parallels Clinical Phenotype Extremes
Authors: CHOW LISA S. , MASHEK DOUGLAS G. , BOSCH TYLER , BANTLE ANNE , PETTERSON MAI , DENGEL DONALD R. , JENSEN MICHAEL D. 
Published: June 2018

Intramyocellular lipid (IMCL) is generally associated with insulin resistance and lipotoxicity. However, the “athlete’s paradox” is well documented, where IMCL levels are similar between athletes and patients with type 2 diabetes despite discrepant levels of insulin sensitivity. Differences in muscle lipid metabolites between aerobically trained, lean, insulin-sensitive (LT) vs. sedentary, overweight/obese, insulin-resistant (OIR) individuals remain insufficiently characterized and may help to explain the “athlete’s paradox.” LT [n=14: 50% females, 28.5±1.6 years (Mean±SE)] and OIR [n=24: 79% females, 29.8±1.6 years] subjects each provided 2 muscle biopsies from the vastus lateralis (bilateral, 6 hours apart, ≥48 hours after last exercise, ≥8 fasting, overnight admission prior to biopsy) for mass spectrometry analysis. At a separate visit, insulin sensitivity was quantified by a hyperinsulinemic-euglycemic clamp (mg glucose/kg FFM/min). As the sequential biopsy results were not significantly different, the results were averaged for each subject. Compared with the OIR group, the LT group had lower BMI (22.3±0.5 vs. 36.2±1.2 kg/m2:p&lt;0.01), higher fitness (VO2max:53.4±2.2 vs. 26.7±1.1 ml/kg/min: p&lt;0.01), and higher insulin sensitivity (M-value: 17.1±0.7 vs. 8±0.5, p&lt;0.01). Muscle triglycerides in the LT group were lower (nmol/mg muscle) in oleic acid (3.2±0.6 vs. 6.0±1.0, p=0.02) and palmitic acid (1.5±0.2 vs. 3.1±0.5, p&lt;0.01) than the OIR group. Diacylglycerol (DAG) and palmitoylcarnitine concentrations were not significantly different. Only in the OIR group, palmitoylcarnitine correlated with the following: oleic acid (r=0.73, p&lt;0.01), palmitic acid (r=0.73, p&lt;0.01) and DAG (dipalmitate:r=0.53, p=0.03, palmitate+oleate: r=0.51, p=0.04). These findings suggest that either incomplete muscle lipid oxidation or increased acylcarnitine generation is present in the OIR group, thus warranting further research on training effects on muscle lipid turnover.

Disclosure
L.S. Chow: Research Support; Self; Eli Lilly and Company, National Institute of Diabetes and Digestive and Kidney Diseases. D.G. Mashek: None. T. Bosch: None. A. Bantle: None. M. Petterson: None. D.R. Dengel: None. M.D. Jensen: Other Relationship; Self; Novo Nordisk A/S. Consultant; Self; Novo Nordisk A/S.
Assessment of Fasting Glucagon Levels in Subjects with Diabetes and Healthy Controls Using ELISA and RIA
Authors: BRUNNER MARTINA , HABERLANDER MAXIMILIAN , SVEHLIKOVA EVA , EBERHARD KATHARINA , STACH ELISABETH , LIPP ROBERT , OBERMAYER-PIETSCH BARBARA M. , PIEBER THOMAS R. , SOURIJ HARALD 
Published: June 2018

Based on the lack of accurate methods for glucagon analysis, it has been suggested that glucagon levels are elevated in subjects with type 1 diabetes. The availability of more specific methods for the determination of glucagon has indicated that actual glucagon levels are lower than previously assumed. This study aimed to characterize fasting glucagon levels in subjects with type 1 diabetes (T1D) and type 2 diabetes (T2D) compared to their nondiabetic counterparts using two different assays. We recruited 20 healthy, 20 T1D and 20 T2D subjects for the trial. Glucagon samples were obtained using BD P800 blood collection tubes and measured with a double-antibody sandwich ELISA (Mercodia) and a RIA (MP Biomedicals). Using the ELISA, healthy subjects had similar glucagon levels compared to T1D. ELISA based glucagon measurements demonstrated significantly higher fasting glucagon levels in T2D as compared to healthy subjects, while RIA measurements tend to be numerically higher, albeit not statistically different (p=0.201). Median glucagon values obtained by RIA were significantly (p=0.0001) higher than those measured by ELISA in a pooled analysis.
In conclusion, T2D show fasting hyperglucagonaemia, whereas T1D present with similar fasting glucagon levels compared to nondiabetic subjects. Furthermore, this study highlights the importance of selective analysis methods in endocrine research.

Disclosure
M. Brunner: None. M. Haberlander: None. E. Svehlikova: None. K. Eberhard: None. E. Stach: None. R. Lipp: None. B.M. Obermayer-Pietsch: None. T.R. Pieber: Consultant; Self; Arecor, AstraZeneca, Eli Lilly and Company, Novo Nordisk A/S, Sanofi. Employee; Self; CBmed. Research Support; Self; Novo Nordisk A/S, AstraZeneca. H. Sourij: Speaker's Bureau; Self; Boehringer Ingelheim GmbH, Novo Nordisk A/S, Amgen Inc., Sanofi, MSD K.K.. Research Support; Self; AstraZeneca, Boehringer Ingelheim GmbH, MSD K.K., GI Dynamics Inc..
Metabolomics Shows an Association of Betatrophin with Bile Acids, Suggesting an Involvement of Betatrophin in Bile Acid–Mediated Metabolic Control
Authors: LEIHERER ANDREAS , MUENDLEIN AXEL , GEIGER KATHRIN , SAELY CHRISTOPH H. , BRANDTNER EVA-MARIA , EBNER JANINE , LARCHER BARBARA , MADER ARTHUR , FRAUNBERGER PETER , DREXEL HEINZ 
Published: June 2018

Betatrophin, also known as ANGPTL8, is secreted by liver and adipose tissue and plays an important role in glucose and lipid metabolism, but the mechanisms behind this remain unclear. Betatrophin is highly activated by active triiodothyronine (T3), a key player in metabolic control, which in turn is activated by bile acids (BA) via the BA-G-protein-coupled receptor TGR5-cAMP-deiodinase (D2), mediating the conversion of prohormone thyroxine to T3. We here measured betatrophin by ELISA and also applied GWAS and targeted metabolomic profiling in 233 serum samples of coronary angiographied patients. We found a correlation between betatrophin and BMI (r=0.142, p&lt;0.001), fasting glucose (r=0.133, p=0.002), insulin (r=0.221, p&lt;0.001), triglycerides (r=0.233, p&lt;0.001), HDL (-0.122, p=0.004), and oxLDL (r=0.247, p&lt;0.001). GWAs also found a genome wide-association between betatrophin and genomic variants in sterol transporter genes ABCG5/G8 and ABCA1. In the metabolomic assay we identified BA as the top metabolites to be associated with betatrophin concentration in serum (CDCA, r=0.234, p&lt;0.001; GDCA, r=0.247, p&lt;0.001; GCA, r=0.269, p&lt;0.001; GCDCA, r=0.268, p&lt;0.001; GLCA, r=0.211, p=0.002; TDCA, r=0.184, p=0.006).
In conclusion, this study for the first time describes the association between betatrophin and BA. As (i) T3 is activated by BA via the BA-TGR5-cAMP-D2 signalling pathway and (ii) T3 is a strong activator of betatrophin, the link between betatrophin concentration and BA suggests that, at least in part, the impact of BA on energy homeostasis and metabolic control may be mediated via betatrophin. Moreover, TGR5 receptors have also been identified on pancreatic islet α- and β-cells and are stimulating insulin secretion in β-cells and able to restore β-cell mass and function under hyperglycemic conditions. Altogether, this may elucidate the impact of betatrophin on lipid and glucose metabolism.

Disclosure
A. Leiherer: None. A. Muendlein: None. K. Geiger: None. C.H. Saely: None. E. Brandtner: None. J. Ebner: None. B. Larcher: None. A. Mader: None. P. Fraunberger: None. H. Drexel: None.
Lactobacillus Gasseri in the Upper Small Intestine Impacts an ACSL3-Dependent Fatty Acid Sensing Pathway That Regulates Whole-Body Glucose Homeostasis
Authors: BAUER PAIGE V. , DUCA FRANK , ZAVED WAISE T.M. , DRANSE HELEN J. , RASMUSSEN-SMALL BRITTANY A. , PURI AKSHITA , RASTI MOZHGAN , LAM TONY K.T. 
Published: June 2018

Long chain acyl CoA synthetase (ACSL)-dependent upper small intestinal lipid metabolism activates preabsorptive pathways to regulate metabolic homeostasis, but whether changes in the upper small intestinal microbiota alter specific fatty acid-dependent pathways to impact glucose homeostasis remains unknown. We here first find that upper small intestinal infusion of Intralipid, oleic acid, or linoleic acid preabsorptively increases glucose tolerance and lowers glucose production in rodents. High-fat feeding impairs preabsorptive fatty acid sensing and reduces upper small intestinal Lactobacillus gasseri levels and ACSL3 expression. Transplantation of healthy upper small intestinal microbiota to high-fat fed rodents restores Lactobacillus gasseri levels and fatty acid sensing via increased ACSL3 expression, while Lactobacillus gasseri probiotic administration to non-transplanted high-fat fed rodents is sufficient to restore upper small intestinal ACSL3 expression and fatty acid sensing.
In summary, we unveil a glucoregulatory role of upper small intestinal Lactobacillus gasseri that impacts an ACSL3-dependent glucoregulatory fatty acid sensing pathway.

Disclosure
P.V. Bauer: None. F. Duca: None. T. Waise: None. H.J. Dranse: None. B.A. Rasmussen-Small: None. A. Puri: None. M. Rasti: None. T.K.T. Lam: None.
Roles of Adipose Tissue VLDL-VLDLR Axis in Energy Metabolism
Authors: KIM JAE BUM , SHIN KYUNG CHEUL , HWANG INJAE , CHOE SUNG SIK 
Published: June 2018

Elevated plasma triglyceride-rich lipoprotein, such as very low-density lipoprotein (VLDL), is considered a risk factor for prevalence of obesity, type 2 diabetes mellitus, and atherosclerosis. VLDL receptor (VLDLR), one of the lipoprotein receptor family proteins, is involved in clearance of circulating VLDL. In obese animals, adipose tissue macrophages (ATMs) contain high level of lipid metabolites, which seems to be linked to pro-inflammatory responses. However, it has not been thoroughly understood whether lipid uptake via VLDLR in macrophages is involved in obesity-induced inflammatory responses and insulin resistance. In this study, we demonstrate that elevated VLDLR in ATMs could accelerate adipose tissue inflammation and glucose intolerance in obesity. Expression of VLDLR was increased in ATMs from obese mice. In VLDL-treated macrophages, the level of ceramides was elevated through VLDLR, which potentiates pro-inflammatory responses and augments M1-like macrophage polarization. Moreover, adoptive transfer of VLDLR knockout bone marrow to wild type mice relieved adipose tissue inflammation and improved insulin resistance in diet-induced obesity. Taken together, these findings suggest that increased VLDL-VLDLR axis in ATMs would aggravate adipose tissue inflammation and insulin resistance in obesity.

Disclosure
J. Kim: None. K. Shin: None. I. Hwang: None. S. Choe: None.
Fasting Glucagon Concentrations Predict Longitudinal Changes in ß-Cell Function of Nondiabetic Humans
Authors: ADAMS J.D. , LAURENTI MARCELLO C. , HURTADO MARIA D. , MAN CHIARA DALLA , COBELLI CLAUDIO , RIZZA ROBERT A. , VELLA ADRIAN 
Published: June 2018

The diabetes-associated allele at rs7903146 in the TCF7L2 locus predisposes to type 2 diabetes (T2DM). Recent work has shown that this variant is associated with impaired postprandial glucagon suppression. Since defects in α-cell function occur independently of impaired β-cell function, we hypothesized that impaired glucagon suppression could accelerate progression to T2DM. Therefore, we recruited 73 nondiabetic subjects with prior (6.7 ± 0.3 years) measurement of β-cell function using the oral minimal model (Baseline) and compared these indices to those obtained during a repeat Experiment (Present). Weight increased slightly, but significantly (2.8 ± 0.7 Kg, p &lt; 0.01) over the period of study. Overall Disposition Index (DI) which expresses β-cell responsivity (ϕ) as a function of insulin action (Si) did not change (1234±160 vs. 1143±116 10-14, dl/kg/min2 per pmol/l, DIBaseline vs. DIPresent, p=0.55). However, there was considerable heterogeneity with a decline in DI associated with impaired Si Baseline after adjusting for age and weight changes (R2 = 0.22, p = 1.2 x 10-3). Of note, fasting glucagon concentrations at the time of initial study ([Glucagon]Baseline) were also significantly and inversely related to DIPresent (R2 = 0.13, p = 8 x 10-3). Baseline nadir and integrated (Area Under Basal-AUB) glucagon concentrations did not predict (p &gt; 0.05) changes in DI. Fasting [Glucagon]Baseline, adjusted for age and weight changes interacts with Si Baseline to predict the longitudinal decline in DI (DIBaseline-DIPresent: (R2 = 0.29, p &lt; 1 x 10-4). Taken together, these data suggest that defects in α-cell function, manifest as elevated fasting glucagon, drive subsequent decline in β-cell function. It remains to be ascertained if defects in postprandial-glucagon suppression attributable to or independent of, diabetes-associated genetic variation in TCF7L2 also interact with defects in fasting glucagon secretion to drive decline in β-cell function in nondiabetic humans.

Disclosure
J. Adams: None. M.C. Laurenti: Other Relationship; Self; GlySens Incorporated. M.D. Hurtado: None. C. Dalla Man: None. C. Cobelli: Research Support; Self; Sanofi-Aventis. Advisory Panel; Self; Novo Nordisk Inc.. R.A. Rizza: None. A. Vella: Research Support; Self; Novo Nordisk Inc., XOMA Corporation. Advisory Panel; Self; VTV Therapeutics, Bayer AG.
Exendin-4, a Glucagon-Like Peptide-1 Receptor Agonist, Attenuates Prostate Cancer Cell Proliferation via Phosphorylation of MKP-1
Authors: KAWANAMI TAKAKO , NOMIYAMA TAKASHI , HAMAGUCHI YURIKO , TANAKA TOMOKO , YANASE TOSHIHIKO 
Published: June 2018

Pleiotropic benefits of incretin therapy beyond glycemic control have been reported and receiving much attention. Cancer is one of major causes of death in patients with type 2 diabetes. We have previously reported Exendin-4(Ex-4), a glucagon-like peptide-1 receptor agonist, attenuates prostate cancer growth by the inhibition of ERK-MAPK phosphorylation (Diabetes 2014). On the other hand, it is well known that MAPK is inactivated and tightly regulated by MAPK phosphatase (MKP) family. Then, we next examined whether MKP could be involved in the anti-proliferative effect of Ex-4 in the prostate cancer cell. In a human prostate cancer cell line, LNCaP cell, MKP-1 was abundantly expressed. Knocking down of MKP-1 using siRNA abolished Ex-4 induced-reduction of LNCaP cell number in growth curve. In addition, Ex-4 treatment significantly increased MKP-1 mRNA expression. To activate its phosphatase activity, Ser359 in the C terminus of MKP-1 is specifically phosphorylated. Ex-4 significantly phosphorylated Ser359 of MKP-1along with time course of dephosphorylating ERK-MAPK. Using Immunoprecipitation assay, we further confirmed that Ex-4 exactly phosphorylated Ser359 of MKP-1. In addition, if we transiently transfected GFP conjugated MKP-1 into LNCaP cells, nuclear translocation of MKP-1 induced by Ex-4 treatment was observed in early phase stimulation. These data suggest that Ex-4 attenuates prostate cancer cell proliferation via phosphorylation of MKP-1 followed by inhibition of ERK-MAPK activation.

Disclosure
T. Kawanami: None. T. Nomiyama: Research Support; Self; MSD K.K., Sanofi-Aventis, Boehringer Ingelheim Pharmaceuticals, Inc., Takeda Pharmaceuticals, Japan. Y. Hamaguchi: None. T. Tanaka: None. T. Yanase: Research Support; Self; MSD K.K., Boehringer Ingelheim Pharmaceuticals, Inc., Takeda Pharmaceuticals, Japan.