bluuebunny/crossref_metadata_2025 huggingface dataset:
1963-P: Short- and Long-Term Empagliflozin Treatment Improves Cardiac Function in Rats with Chronic Heart Failure
Authors: SOULIÉ MATTHIEU , STEPHAN YOHAN , NICOL LIONEL , HENRY JEAN-PAUL , RICHARD VINCENT , PIEPER MICHAEL , MULDER PAUL
Published: June 2020

Introduction: The SGLT2 inhibitor empagliflozin (EMPA) exerts beneficial cardiovascular effects in type-2 diabetes, but whether this occurs in chronic heart failure (CHF) is unknown. Thus we investigated, using a rat model whether EMPA exhibits protective effect in chronic heart failure (CHF).

Methods: Rats with CHF were treated with EMPA (30 mg/kg PO for 7 days starting 83 days after coronary artery ligation or 90 days starting 7 days after coronary artery ligation) to assess effects on left ventricular (LV) function and hemodynamics (echocardiography, LV catheterization).

Results: After 90 days untreated CHF rats presented LV systolic and diastolic dysfunction, illustrated by the decreases in LV end-systolic pressure (LV ESP) and in LV end-systolic pressure volume-relation (LV ESPVR) as well as the increases in LV end-diastolic pressure (LV EDP) and LV end-diastolic pressure volume-relation (LV EDPVR). Seven- and ninety-day EMPA treatment improved systolic and diastolic LV function, illustrated by the increases in LV ESP and in LV ESPVR as well as the reductions in LV EDP and in LV EDPVR.

Conclusion: Short- and long-term EMPA treatment prevents LV dysfunction in rats with CHF. These results suggest that EMPA may exert protective effects in humans with CHF.

Disclosure

M. Soulié: None. Y. Stephan: None. L. Nicol: None. J. Henry: None. V. Richard: None. M. Pieper: Employee; Self; Boehringer Ingelheim Pharmaceuticals, Inc. P. Mulder: Research Support; Self; Bayer Healthcare Pharmaceuticals Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Poxel SA.

Funding

Boehringer Ingelheim
1964-P: Slug Epigenetically Represses Adipose Thermogenic Programs
Authors: KANG QIANQIAN , JIANG LIN , RUI LIANGYOU
Published: June 2020

Thermogenic fat, such as brown adipose tissue (BAT) and beige fat, gains increasing attention due to its ability to protect against obesity and type 2 diabetes. Brown adipocytes and beige adipocytes contain dense mitochondria that burn glucose and free fatty acids to produce heat, and mitochondrial Ucp1 mediates heat production. Coactivator PGC1α is a master regulator of mitochondrial biogenesis and Ucp1 expression, and profoundly influences the energy expenditure capability of thermogenic fat. We attempted to delineate transcriptional regulators that govern thermogenic fat activity through PGC1α, and identified transcriptional repressor Slug. Both human and mouse PGC1α promoters contain multiple Slug binding motifs. Slug potently suppressed the activity of PGC1α promoter luciferase reporters but not mutant PGC1α promoters lacking Slug motifs. Consistently, Slug physically bound to the PGC1α promoter and decreased the levels of PGC1α promoter H3K9 acetylation, a transcriptionally-active epigenetic mark, presumably by recruiting HDAC1/2 to the promoter. In line with this notion, treatment with HDAC1/2 inhibitor trichostatin A abrogated the ability of Slug to suppress PGC1α promoter luciferase reporters. Remarkably, deletion of Slug substantially increased expression of PGC1α and Ucp1 in both BAT and inguinal fat in mice, and increased H3K9 acetylation levels on the PGC1α promoter in BAT. Slug-deficient BAT had increased O2 consumption rates and thermogenesis capability. Slug knockout mice were resistant to high fat diet-induced obesity, insulin resistance, glucose intolerance, and fatty liver disease. Likewise, adipocyte-specific deletion of Slug also ameliorated HFD-induced glucose intolerance. Unlike global Slug knockout mice, adipocyte-specific Slug knockout mice displayed mild metabolic phenotypes.

In conclusion, our data suggest that Slug regulates thermogenic fat energy expenditure at least in part by epigenetically suppressing the PGCα-mitochondria axis.

Disclosure

Q. Kang: None. L. Jiang: None. L. Rui: None.
1976-P: Cardiovascular Safety of Sulfonylureas in Type 2 Diabetes: Effect Modification by Obesity?
Authors: SUISSA KARINE , DOUROS ANTONIOS , AZOULAY LAURENT , FILION KRISTIAN B. , SCHNEEWEISS SEBASTIAN
Published: June 2020

Background: Pharmacokinetic studies suggest that adiposity may modify antidiabetic (AD) medication efficacy and safety via altered drug distribution. While sulfonylureas (SU) have been linked to a higher cardiovascular (CV) risk, with inconsistent results, the role of obesity remains unclear. We evaluated the effect of obesity on CV risk with SU as first-line therapies for type 2 diabetes in a clinical practice. Methods: Using the UK’s Clinical Practice Research Datalink, we conducted a cohort study of patients initiating AD treatment. Initiators of SU monotherapy were matched with initiators of metformin (MET) monotherapy on a high-dimensional propensity score. Patients were censored at the time of discontinuation or addition of another AD drug. We used Cox proportional hazards models within body mass index (BMI) categories (< 25 kg/m2 (normal weight; 26%), 25-30 kg/m2 (overweight; 42%), ≥ 30 kg/m2 obese; 32%)) to estimate hazard ratios (HR) of major adverse cardiovascular events (MACE), individual components of MACE, and all-cause mortality, comparing SU with MET.

Results: A total of 94,750 patients with type 2 diabetes initiated SU or MET. We matched 13,999 initiators of SU with 13,999 MET initiators. The overall HR of MACE comparing SU with MET was 1.23 (95% CI: 1.08-1.39); the HR was 1.33 (95% CI: 1.02-1.74) among obese patients, 1.27 (95% CI: 1.04-1.55) for overweight patients, and 0.99 (95% CI: 0.77-1.28) among normal weight patients. Similarly, the risk of all-cause mortality, CV death and ischemic stroke with SU was highest in obese individuals, with evidence of interactions for all-cause mortality and stroke.

Conclusion: Sulfonylureas as a first-line monotherapy for type 2 diabetes is associated with a higher risk of MACE compared with MET. Our data suggest that this effect might be strongest in obese patients, with no increased risk in normal weight patients. To ensure the best response to treatment, BMI level may be considered when choosing MET over SU for first-line treatment.

Disclosure

K. Suissa: None. A. Douros: None. L. Azoulay: Consultant; Self; Janssen Pharmaceuticals, Inc., Pfizer Inc. K.B. Filion: None. S. Schneeweiss: None.
1981-P: Impaired Exercise Lipid Oxidation Is Associated with Poor Metabolic Health, Not Excess Body Fat Per Se
Authors: ARAD AVIGDOR D. , DIMENNA FREDERICK J. , KITTRELL HANNAH D. , KISSILEFF HARRY R. , ALBU JEANINE
Published: June 2020

Introduction: It is not clear whether impaired exercise lipid oxidation is associated with excess body-fat or changes in metabolic health often associated with the overweight/obese state. Mixed findings may reflect lack of control for key variables including: 1) acute energy balance and macronutrient composition of the diet; 2) intensity and duration of exercise; and 3) subject characteristics including fat-free mass (FFM), fitness and, perhaps most importantly, metabolic health (e.g., insulin resistance).

Purpose: To determine whether excess body-fat or loss of metabolic health is associated with altered fuel metabolism during exercise.

Methods: Eight metabolically healthy (FH- and ≤1 MetSyn) normal-weight (BMI, 19-24 kg∙m-2) (MHNW) and 8 overweight/obese (26-35 kg∙m-2) (MHO) sedentary adults, and 7 metabolically unhealthy (FH+ and ≥ 2 MetSyn) normal-weight (MUNW) and 7 overweight/obese (MUO) sedentary adults, controlled for age (18-45 yr), sex, and fitness level (≤ “average”), completed a 10-day weight-stable (controlled feeding) testing protocol that included measurement of V?O2peak, RMR, body-fat %, OGTT and lipid oxidation during 45 min of moderate-intensity cycling. ANCOVA with adjustment for rate of O2 consumption (ml∙min-1∙kgBW-1) was used with contrasts to compare indices of lipid oxidation among the four groups.

Results: Adjusted means over both sexes for lipid oxidation during exercise, expressed as rate (mg∙min-1∙kgFFM-1), RER and percent total energy expenditure were significantly different between groups (p<0.05). There was a significant difference between MHNW vs. MUO for all indices (p<0.05), and between MUNW vs. MHO for rate (p<0.025). Tukey post-hoc also revealed a significant difference between MHNW vs. MUNW for all indices.

Conclusion: We found that impaired exercise lipid oxidation previously ascribed to the overweight/obese state was specifically associated with the loss of metabolic health as opposed to the overweight/obese state per se.

Disclosure

A.D. Arad: None. F.J. DiMenna: None. H.D. Kittrell: None. H.R. Kissileff: None. J. Albu: None.
1991-P: Intensive Lifestyle Intervention Does Not Reduce Racial and Ethnic Disparities in Achievement of Optimal Glycemic Control
Authors: HAYES JACQUELINE F. , BERTONI ALAIN , PILLA SCOTT J. , WING RENA R.
Published: June 2020

African Americans and Hispanics with type 2 diabetes have worse glycemic control relative to non-Hispanic whites. The Look AHEAD randomized trial demonstrated that an intensive lifestyle intervention for weight loss (ILI), versus diabetes support and education (DSE), improved HbA1c among overweight/obese adults with type 2 diabetes. We examined whether ILI reduced racial/ethnic disparities in achieving optimal glycemic control (HbA1c <7%). We used a GEE model to examine the effects of race/ethnicity, treatment arm, and their interaction on achieving HbA1c <7% over 8 years. Among 4,889 participants (16% African American, 14% Hispanic), more achieved HbA1c <7% in ILI vs. DSE in years 1-4 (p<0.001). However, significantly fewer Hispanic and African Americans achieved HbA1c <7% (p<0.001). The race by treatment interaction was not significant at any time point. These findings demonstrate persistent racial/ethnic disparities in glycemic control in a clinical trial population over eight years, which were not reduced by an effective lifestyle intervention. More research is needed to develop interventions that improve diabetes outcomes while reducing disparities.

Disclosure

J.F. Hayes: None. A. Bertoni: None. S.J. Pilla: None. R.R. Wing: None.

Funding

National Institutes of Health
1999-P: Intranasal Oxytocin Improves Lean Muscle Mass in Older Adults with Sarcopenic Obesity: A Pilot Study
Authors: ESPINOZA SARA E. , LEE JESSICA , WANG CHEN-PIN , MACCARTHY DANIEL J. , GANAPATHY VINUTHA , PASCUCCI CHIARA , MUSI NICOLAS
Published: June 2020

Obesity leads to sarcopenia and poor physical function with aging. Evidence in animals and in middle-age humans suggests that the pituitary hormone oxytocin reduces appetite, promotes weight loss, and improves glucose tolerance while preserving lean muscle mass. We studied oxytocin’s effect on body mass index (BMI), glucose tolerance, muscle mass, and physical function in an older adult population with sarcopenic obesity. Twenty-one older (≥60 yrs), obese (30-43 kg/m2), sedentary (<2 exercise/week) adults with slow gait (<1 m/sec) were randomized to either intranasal oxytocin (24 IU QID) or placebo for 8 wks. Those with diabetes, mod-severe chronic diseases, and cognitive impairment (Mini-Cog <3) were excluded. Pre and post BMI, oral glucose tolerance test (OGTT), Hemoglobin A1c (HbA1c), physical function (short physical performance battery [SPPB]), and whole body lean and fat mass (via DXA) were assessed. Generalized linear mixed effects models were used to evaluate the effect of oxytocin on these measures. Age was 67.5 ±5.4 yrs, 71% were female, BMI was 36.0 ±3.6 kg/m2, fasting plasma glucose (FPG) was 92.0 ±8.9 mg/dL, HbA1c was 5.7 ±0.4%, 2-hour OGTT glucose was 140.8 ±4.1 mg/dL, SPPB was 9.2 ±1.9, fat mass was 45429.1 ±7037.4 g, and lean mass was 49892.4 ±10470.9 g. At 8 wks, total lean mass increased significantly (2,250 g) in the oxytocin group (pre- vs. post-treatment difference of -690.5 g in placebo and +1,559.5 g in the oxytocin group, p<0.01). Oxytocin did not lead to significant changes in BMI, FPG, HbA1c, 2-hour OGTT glucose, fat mass or SPPB.

In conclusion, this preliminary data suggests that oxytocin leads to improvement in whole body lean mass. Future studies are needed in a larger population to determine whether older adults with sarcopenic obesity may benefit from treatment with oxytocin to improve lean muscle mass. Further work is needed to determine whether these improvements ultimately lead to improved physical function and other parameters of healthspan with aging.

Disclosure

S.E. Espinoza: None. J. Lee: None. C. Wang: None. D.J. MacCarthy: None. V. Ganapathy: None. C. Pascucci: None. N. Musi: None.

Funding

Claude D. Pepper Older Americans Independence Centers (University of Texas Health Science Center at San Antonio; University of Texas Medical Branch Galveston); Clinical Translational Science Award Programs (University of Texas Health Science Center at San Antonio; University of Texas Medical Branch Galveston); University of Texas Health Science Center at Houston
20-LB: Time since Diagnosis Is Associated with Subclinical Cardiovascular Disease in Adults with Type 1 Diabetes
Authors: RODRIGUEZ FATIMA M. , RIVAS BERNARDETTE , LARA CAROLINA , URIBE DANIEL , MARTAGON ALEXANDRO J. , ALMEDA-VALDES PALOMA , GARAY MORA JUAN A. , PEDRAZA NATALIA RAMIREZ
Published: June 2020

Individuals with type 1 diabetes have increased morbidity and mortality due to cardiovascular disease (CVD), being the cause of death in 40% of these patients. A high proportion develop CVD before 50 years. Objective of this study was to explore factors associated with subclinical cardiovascular disease using aortic stiffness markers including pulse wave velocity (APWv), aortic augmentation index (AIx) and carotid intima-media thickness (cIMT).

Material and Methods: Cross-sectional study carried out in the Type 1 Diabetes Clinic of a tertiary center in Mexico City. Demographic and biochemical variables were evaluated. Anthropometric and body composition analysis was performed using bioelectrical impedance. Assessment of the APWv and cIMT was carried out using ultrasound and AIx with aortic tonometry. Statistical analyses were performed using SPPS version 21, a P value < 0.05 was considered significant.

Results: 49 patients have been included, 25(51%)women. Mean age of the participants was 38.1±11.9 years. Mean age at diagnosis was 17± 8.8 years and time median time since diagnosis 20(range 6 to 43) 17± 8.8 years. A positive correlation was found between APWv and time since diagnosis, total cholesterol and visceral adipose tissue and a negative association with eGFR. The AIx showed positive correlation with time since diagnosis, age, body mass index (BMI) and systolic blood pressure. The cIMT showed a positive correlation with time since diagnosis, BMI and a negative association with eGFR. We did not find associations between the stiffness markers and A1c or albuminuria. In the linear regression analysis only time since diagnosis remained significantly and independently associated with the AIx after adjusting for age, BMI and systolic blood pressure.

Conclusions: This preliminary report shows that time since type 1 diabetes diagnosis is positively and independently associated with markers of aortic rigidity (AIx) in this population of young adults with type 1 diabetes.

Disclosure

F.M. Rodriguez: None. B. Rivas: None. C. Lara: None. D. Uribe: None. A.J. Martagon: None. P. Almeda-Valdes: None. J.A. Garay Mora: None. N. Ramirez Pedraza: None.
2033-P: In Vitro Analysis of Bisphenol A Effects on Beta-TC-6 Cells Function
Authors: ANASTASIOU IOANNA , ELEFTHERIADOU IOANNA , TENTOLOURIS ANASTASIOS , ANGELOPOULOU ANDRIANI , KOSTA OURANIA , MOUROUZIS IORDANIS , TENTOLOURIS NIKOLAOS
Published: June 2020

Bisphenol A (BPA) is an organic compound that is widely used in plastic products. It acts as an endocrine disruptor capable of mimicking or modifying the activity of endogenous hormones. Recent data have shown that exposure to BPA increases the risk of type 2 diabetes. The aim of this study was to examine the effects of BPA on beta-TC-6 mice cells. Cells were incubated with serial dilutions of BPA: control group, 0.002μM, 0.02μM, 0.1μM, and 0.2μM for 12, 24, 48 and 72 hours. Cell viability and proliferation levels were determined by measuring intracellular ATP levels. BPA effects on beta-TC-6 cells were investigated by studying gene expression regulated at the transcriptional RNA level by real time PCR technique (citrate synthase and ATP synthase 6) and protein concentrations regulated at the translational levels by western blot analysis. The aging rate of cells was studied using SenTraGor TM. Exposure of beta-TC-6 cells to all BPA concentrations resulted in significant decreases of intracellular ATP levels when compared with the control group (all p<0.05). Moreover, exposure of beta-TC-6 cells to 0,2μM BPA concentration for 24 and 48 hours resulted in significant increases in the relative gene expression levels and in increased expression of proteins involved in apoptosis. The percentage of aging cells was >20% of total number of cells 24 hours after incubation at the 2 higher concentrations of BPA and was significantly increased when compared with the control group and the lower concentration of BPA. BPA affects viability, function and aging of beta-TC-6 cells. BPA presumably increases apoptosis rate and induces mitochondrial dysfunction on beta-TC-6 cells in a dose-dependent manner.

Disclosure

I. Anastasiou: None. I. Eleftheriadou: None. A. Tentolouris: None. A. Angelopoulou: None. O. Kosta: None. I. Mourouzis: None. N. Tentolouris: None.
2035-P: Involvement of Circular RNAs in Proinflammatory Cytokines-Mediated Beta-Cell Dysfunction
Authors: WANG ZHEN , ZHENG YING , ZHOU ZHIGUANG
Published: June 2020

Background: Exposure of pancreatic β-cell to proinflammatory cytokines released by islet-infiltrating immune cells will lead to impaired insulin production and secretion as well as β-cell apoptosis during the initial phase of type 1 diabetes (T1D). Circular RNAs (circRNAs) were newly discovered as a novel class of non-coding RNAs that are involved in many diseases. As little is known about their role in insulin-secreting cells, this study aimed to evaluate their contribution to inflammation-induced β-cell dysfunction.

Methods: CircRNA expression proﬁle in MIN6 cells stimulated with a mix of cytokines, including IL-1β, IFN-γ, and TNF-α, was detected by circRNA microarrays. The diﬀerentially expressed circRNAs were validated by qRT-PCR. The involvement of selected circRNAs was tested after their inhibition in MIN6 cells. MicroRNA target prediction software and multiple bioinformatic approaches were used to construct a map of circRNA-microRNA-mRNA interactions and predict possible functions and pathways of the circRNAs.

Results: 1020 upregulated and 902 downregulated circRNAs were detected in cytokines-treated β-cells with a set filter fold-change ≧1.5. By qRT-PCR, circRNA 006029 and 013053 were furtherly proved to be increased by 2.1 fold and 3.7 fold, while circRNA 000286 and 017277 were downregulated by 3.4 fold and 1.9 fold. Inhibition of circRNA 000286 and 017277 in β-cells, with or without stimulation of cytokines, could promote β-cell apoptosis and affect glucose-induced insulin secretion. GO analysis enriched terms such as anatomical structure development and intracellular, and the top pathways included Pathways in cancer and MAPK signaling pathway. It was also speculated that the two circRNAs may regulate the key genes involved in β-cell apoptosis and function, such as Bcl2 and Vamp2.

Conclusion: Our data showed circRNAs as novel regulators in proinflammatory cytokines-mediated β-cell dysfunction, and suggested the involvement of circRNAs in the development of T1D.

Disclosure

Z. Wang: None. Y. Zheng: None. Z. Zhou: None.

Funding

National Natural Science Foundation of China (81502359)
2038-P: The Somatostatin Analog Pasireotide Reduces Pancreatic ß-Cell Function and Survival, and Both Incretin-Based Drugs and Irisin Revert These Effects
Authors: NATALICCHIO ANNALISA , BIONDI GIUSEPPINA , MARRANO NICOLA , VINCENTI LEONARDO , CIGNARELLI ANGELO , PERRINI SEBASTIO , LAVIOLA LUIGI , GIORGINO FRANCESCO
Published: June 2020

Pasireotide is a new-generation somatostatin analog used for the treatment of acromegaly, Cushing’s disease and neuroendocrine tumors. However, due to its high affinity for somatostatin receptors (SSTR) 2 and 5, highly expressed in enteroendocrine- and pancreatic β-cells, it can reduce insulin, GLP-1 and GIP release and increase glucagonemia, causing marked hyperglycemia in some patients. The diabetogenic effects of pasireotide are significantly reduced in vivo by the co-administration of liraglutide or vildagliptin. The aim of this study was to evaluate the effects of pasireotide on β-cell survival and function, and the ability of molecules with known beneficial action on β-cells (incretin-based drugs and irisin, a myokine with β-cellular trophic properties) to prevent these effects. In INS-1E cells, both acute and chronic administration of pasireotide 10-50 nM reduced glucose-induced insulin secretion by 30% and 50% respectively and proinsulin mRNA levels by 20%, without altering cellular insulin content. Furthermore, pasireotide induced apoptosis in INS-1E cells and human pancreatic islets. Pretreatment with both incretin-based drugs (exendin-4, lixisenatide, liraglutide, saxagliptin) and irisin prevented pasireotide-induced apoptosis in INS-1E cells. In addition, pasireotide increased the protein levels of SSTR2 (2-fold) but not of SSTR5. Among the protective molecules examined, only irisin was able to prevent this increase.

In conclusion, pasireotide can induce hyperglycemia and diabetes via direct effects on β-cells, resulting in reduced insulin secretory capacity and survival. Both GLP-1 receptor agonists and DPP-4 inhibitors and irisin can reduce the proapoptotic effects of pasireotide, acting through partially different molecular mechanisms. These results demonstrate for the first time a functional antagonism between SSTR2/5 activation and incretin-based drugs or irisin in pancreatic β-cells.

Disclosure

A. Natalicchio: Consultant; Self; AstraZeneca, Novo Nordisk Inc., Sanofi-Aventis. G. Biondi: None. N. Marrano: None. L. Vincenti: None. A. Cignarelli: None. S. Perrini: None. L. Laviola: Advisory Panel; Self; Abbott, AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Novo Nordisk Inc., Roche Diabetes Care, Sanofi-Aventis. Speaker’s Bureau; Self; Abbott, Medtronic. F. Giorgino: Advisory Panel; Self; AstraZeneca, Eli Lilly and Company, Novo Nordisk Inc., Roche Diabetes Care, Sanofi. Consultant; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., LifeScan, Inc., MedImmune, Merck Sharp & Dohme Corp., Roche Diabetes Care, Sanofi. Research Support; Self; Eli Lilly and Company, LifeScan, Inc., Takeda Development Centre Europe Ltd.

Funding

Novartis
2042-P: Loss of Apoptosis Repressor with Caspase Recruitment Domain Promotes High-Fat Diet Induced Hyperglycemia In Vivo
Authors: TEMPLIN ANDREW T. , SCHMIDT CHRISTINE R. , HOGAN MEGHAN F. , ESSER NATHALIE , KITSIS RICHARD N. , HULL REBECCA L. , ZRAIKA SAKENEH , KAHN STEVEN E.
Published: June 2020

Apoptosis repressor with caspase recruitment domain (ARC) is an endogenous inhibitor of apoptosis signaling. We previously showed ARC is expressed in β cells and ameliorates amyloid-induced β-cell death in vitro. More recently, we found that wild type (WT) and whole-body ARC knockout (KO) mice on an FVB background fed a normal chow diet exhibit no differences in islet area, β-cell area, or α-cell area at 16 (n=5) or 35 weeks (n=7-8) of age. In the present study, we sought to determine whether ARC plays a role in maintaining glycemia in response to the challenge of high fat diet (HFD, 60% kcal from fat) feeding in vivo. At 12 weeks of age, just prior to starting 24 weeks of HFD, ARC KO mice displayed lower body weight than WT mice (0 wks: 26.2±0.6 vs. 30.6±0.8 g; p<0.01; n=13), and this weight difference persisted throughout the HFD study (24 wks: 44.7±2.5 vs. 51.9±1.0 g; p=0.04, n=4-9). Random plasma glucose (PG) was not different between genotypes prior to HFD feeding. With HFD challenge, PG increased significantly in ARC KO but not WT mice (see Table). This elevation in PG in ARC KO mice was observed after 4 weeks of HFD and remained throughout the study. These data indicate that loss of ARC promotes hyperglycemia in response to HFD feeding in vivo. Whether this hyperglycemia in ARC KO mice arises from impaired β-cell compensation due to reduced β-cell mass or function remains to be determined.

Disclosure

A.T. Templin: None. C.R. Schmidt: None. M.F. Hogan: None. N. Esser: None. R.N. Kitsis: None. R.L. Hull: None. S. Zraika: Research Support; Self; Novartis Pharmaceuticals Corporation. S.E. Kahn: Advisory Panel; Self; Boehringer Ingelheim International GmbH, Eli Lilly and Company, Intarcia Therapeutics, Janssen Scientific Affairs, LLC., Merck & Co., Inc., Novo Nordisk A/S, Pfizer Inc.

Funding

U.S. Department of Veterans Affairs (I01-BX001060, IK2-BX004659); National Institutes of Health (P30DK017047)
2051-P: Human Autoantibodies to SerpinB13 Are Both Protective and Functional in Type 1 Diabetes
Authors: KRYVALAP YURY , CZYZYK JAN
Published: June 2020

Our laboratory has identified a novel autoantibody (AA) to serpinB13, a protease inhibitor of cathepsin L, and has found an association of this AA with protection from type 1 diabetes (T1D) in subjects enrolled in the Diabetes Prevention Trial for Type 1 Diabetes (DPT-1). Our additional studies with a monoclonal antibody (mAb) to serpinB13 confirmed these observations in mouse, and implicated this mAb in a protease-mediated cleavage of the Notch 1 receptor as the mechanism of development of pancreatic Ngn3+ endocrine progenitors and resistance to severe diabetes. Whether human AA to serpinB13 plays a similar active role in protection against T1D remains unclear. To examine the potential functionality of human serpinB13 AA, we dialyzed DPT-1 serum samples that were either positive or negative for serpinB13 AA and used them to stimulate mouse embryonic pancreas explants (E12.5) during a 48-hour in vitro culture. Using a quantitative IF microscopy approach, we found that pancreas explants exposed to serpinB13 AA positive serum samples had 50% more Ngn3+ cells compared with pancreas explants incubated with serpinB13 AA negative samples (p=0.0029). This effect was dependent on serpinB13AA rather than other serum factors as positive serum samples immunodepleted of this AA were no longer able to stimulate development of additional Ngn3+ cells (p=0.0016). These data demonstrate that serpinB13 AA is actively involved in regulating the pathways that control development of endocrine cell lineage in the pancreas. Consequently, to our knowledge, serpinB13 AA is the first example of an autoantibody that is not solely a biomarker, but also an active player responsible for improved outcomes in T1D. To examine the role of embryonic serpinB13 AA in human diabetes in future, we aim to measure serpinB13 AA in pregnant women with T1D, or at significant risk for this disease, and assess its impact on the development of diabetes in their offspring after birth.

Disclosure

Y. Kryvalap: None. J. Czyzyk: None.

Funding

American Diabetes Association (I-17-ICTS-083 to J.C.); National Institutes of Health (DK10873901A1)
2068-P: Beta-Cell Compensation to Pubertal Insulin Resistance Is Compromised in High-Fat Fed Rats and Impairs Glucose Homeostasis Later in Life
Authors: CASTELL ANNE-LAURE , FERGUSSON GRACE , ETHIER MÉLANIE , TREMBLAY CAROLINE , GHISLAIN JULIEN , POITOUT VINCENT
Published: June 2020

Puberty is a time of hormonal changes associated with insulin resistance (IR). Although insulin sensitivity is restored at the end of puberty in healthy youth, it does not resolve in obese adolescents leading to an increased risk of metabolic disease such as T2D. During pregnancy-induced IR, pancreatic β cells increase their functional mass to maintain glucose homeostasis. During puberty, however, the mechanism of β-cell compensation to IR and its role in glucose metabolism in adulthood have not been established. In this study we characterized pancreatic β-cell adaptation to pubertal IR in rats and evaluated the effect of metabolic stress during puberty on glucose homeostasis in adult animals.

Methods: Wistar rats were fed a chow or high fat diet (HFD) during puberty. Fasted plasma insulin and glucose tolerance were determined from weaning to adulthood. β-cell proliferation was assessed by immunostaining of pancreatic cryosections for Ki67 and insulin or Nkx6.1. β-cell mass was measured by morphometric analysis of insulin staining. Isolated islets from Wistar rats were exposed during 72h to the serum of prepubertal, pubertal, or postpubertal animals and β-cell proliferation was evaluated by flow cytometry using insulin and EdU antibodies.

Results: During puberty, glucose intolerance was associated with an increase in insulin levels, suggestive of IR. Accordingly, puberty was characterized by a pulse in β-cell proliferation and a rise in β-cell mass. Pubertal but not pre or post pubertal rat serum induced β-cell proliferation in isolated islets. HFD led to a decrease in β-cell proliferation during puberty with impaired glucose tolerance and defective insulin secretion in adult animals.

Conclusion: During puberty in rats, β cells proliferate to compensate for IR. Metabolic stress during puberty impairs glucose homeostasis later in life. Future studies will identify the circulating factor(s) that trigger β-cell expansion during puberty.

Disclosure

A. Castell: None. G. Fergusson: None. M. Ethier: None. C. Tremblay: None. J. Ghislain: None. V. Poitout: None.
208-OR: Emc10emc10, a Novel Circulating Factor for Systemic Energy and Metabolic Homeostasis
Authors: LI YANLIANG , WANG XUANCHUN , QIANG GUIFEN , MCCANN MAXIMILIAN A. , GIL VICTORIA , BLÜHER MATTHIAS , WEE LIEW CHONG
Published: June 2020

Proteins secreted from metabolic organs play critical roles in fine-tuning and maintenance of systemic metabolic and energy homeostasis. In this study, we identified a novel obesity-regulated circulating protein, scEmc10 (secreted-isoform of endoplasmic reticulum membrane complex subunit 10), that regulates systemic energy homeostasis. We initially observed that scEmc10 is modulated in adipose tissues in diet-induced obesity (DIO) models and subsequently in obese patients. Using an in-house-developed chemiluminescent immunoassay, we found that circulating Emc10 is significantly upregulated in overweight and obese patients and can be normalized by bariatric surgery-induced weight loss. Subsequently, we observed that ablation of Emc10 protects mice from DIO and associated metabolic dysregulation. Conversely, enhanced circulating Emc10 by expression of secretable AAV-hscEmc10 in the liver promotes obesity and associated metabolic dysfunctions in mice fed with either chow or high fat diet. Subsequent metabolic analysis revealed that Emc10 KO mice on HFD have elevated whole body energy expenditure compared to WT controls via an increase in oxygen consumption in both the brown and inguinal subcutaneous fat. Our mechanistic analysis demonstrated that ablation of scEmc10 promotes adaptive thermogenesis in adipocytes via activation of the PKA signaling pathway and its downstream targets, particularly CREB and p38MAPK. Finally, we also showed that neutralization of scEmc10 in the circulation with a monoclonal antibody reduced body weight and improved diet-induced metabolic dysfunction in obese mice. Our findings implicate Emc10 as a novel therapeutic target for counteracting the development of obesity and obesity-induced metabolic dysfunction.

Disclosure

Y. Li: None. X. Wang: None. G. Qiang: None. M.A. McCann: None. V. Gil: None. M. Blüher: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk A/S, Sanofi. Speaker’s Bureau; Self; Amgen, Novartis AG. C. Liew: None.

Funding

National Institutes of Health (R01DK090210, R01DK109015); National Natural Science Foundation of China (81070647, 81370936, 81873645, 81873853)
2082-P: A Negative Regulatory Role of Insulinoma Beta Cell–Derived Exosomes in Glucose-Stimulated Insulin Secretion of Beta-Cells by Upregulating Exosomal MicroRNAs-Associated Signals
Authors: LIU SHING-HWA , WU CHENG-TIEN , YU CHIA-CHING
Published: June 2020

Background: In conditions of diabetes, exosomes have been suggested to play the roles in the pathological processes in both type 1 and type 2 diabetes. Exosomes released from both high-concentration glucose- and cytokine-treated β-cells induced β-cell apoptosis. Pancreatic cancer-derived exosomes have also been found to cause paraneoplastic β-cell dysfunction. Here, we further investigated the effects and mechanisms of insulinoma β-cell-derived exosomes on glucose-stimulated insulin secretion.

Methods: Exosomes from insulinoma β-cell lines RIN-m5f or NIT-1 were prepared by ExoQuick-TC™, and identified its characteristics by Western blotting and nanoparticle tracking analysis. For in vitro study, exosomes at the concentrations of 1-30 μg/mL were used. For in vivo study, ICR mice were treated with PBS or exosomes (30 μg/100 μL) for 4 weeks by tail vein intravenous injection twice a week. The miRNA profile was determined by Next Generation Sequencing (NGS) analysis.

Results: Exosomes from insulinoma β-cells did not affect the cell viability, but significantly inhibited the glucose-stimulated insulin secretion of naïve β-cells. Exogenously administration of exosomes derived from insulinoma β-cells to mice also showed the dysregulation of glucose tolerance and serum insulin levels. Moreover, the results of NGS showed that exosomes may transfer miR-1224, -122-5p, -133a-3p, -10b-5p, -423-5p, -409a-3p to affect insulin secretion-related genes/proteins in β-cells. Exosomes also significantly reduced the protein expressions of phosphorylated Akt, Ca2+/calmodulin-dependent protein kinase-II, and glucose transporter-2 in β-cells, which could be reversed by inhibition of exosome uptake.

Conclusion: Exosomes released from insulinoma β-cells are capable of upregulating exosomal miRNAs-associated signals to dysregulate glucose-stimulated insulin secretion in naïve β-cells.

Disclosure

S. Liu: None. C. Wu: None.

Funding

Ministry of Science and Technology of Taiwan (107-2314-B-002-031-MY3)
2090-P: Noradrenergic Stimulus as a Potential Inducer of Human ß-Cell Dedifferentiation
Authors: CINTI FRANCESCA , FANTUZZI FEDERICA , CARFÍ ANDREA , MEZZA TERESA , ASSUNTA CEFALO CHIARA MARIA , MOFFA SIMONA , SORICE GIAN PIO , GIACCARI ANDREA , CNOP MIRIAM
Published: June 2020

β dedifferentiation is recognized as one of the main mechanisms responsible for the disappearance of β cells from pancreatic islets of diabetic subjects, but the underlying process is still unclear. Noradrenergic innervation is known to inhibit insulin secretion, and in pancreas of diabetic subjects a 3-fold increase of noradrenergic fibers was observed compared to nondiabetic subjects, directly related to the % of dedifferentiated cells within the islets. The increase in fibers has been associated with worsening β cell function, suggesting a role in the pathogenesis of the disease and perhaps in the process of dedifferentiation. The aim of our study was to use in vitro human β cell models to explore a direct role of innervation in the process of noradrenergic dedifferentiation. The human β cell line EndoC-βH1 was exposed to different concentrations of noradrenaline (NA) (0.4 μM, 4 μM and 40 μM) for 24 and 72 h. The expression of β cell dedifferentiation markers was assessed before and after stimulation of the α2A adrenergic receptor, by morphology (immunofluorescence (IF)), qPCR and ELISA. FGF2 (100 ng/mL), a known inducer of β dedifferentiation in vitro, was used as a positive control. NA treatment did not have any impact on β cell viability, while, as expected, it slightly reduced insulin secretion after 24 h. The expression of β cell dedifferentiation markers (ALDH1a3) was increased by approximately 30% after stimulation with NA, while mature β cell marker were reduced (NKX6.1) up to 60% after 72 h (by IF detection). Moreover, the mRNA expression of FOXO1, the main transcription factor involved in the dedifferentiation process, was reduced up to 35.4% after 72 h stimulation with NA. We observed a dose and time dependent pattern in all the experiments.

In conclusion, the data suggest a direct role of noradrenergic fibers in the dedifferentiation process, potentially identifying a new target for the prevention and therapy of type 2 diabetes.

Disclosure

F. Cinti: None. F. Fantuzzi: None. A. Carfí: None. T. Mezza: None. C. Cefalo: None. S. Moffa: None. G. Sorice: None. A. Giaccari: Speaker’s Bureau; Self; Amgen, AstraZeneca, Eli Lilly and Company, Merck Sharp & Dohme Corp., Mundipharma, Novo Nordisk A/S, Sanofi-Aventis. M. Cnop: None.

Funding

European Foundation for the Study of Diabetes
2093-P: Tetraspanin7-Mediated Inhibition of Beta-Cell Voltage-Dependent Calcium Channels Regulates Glucose-Stimulated Insulin Secretion
Authors: DICKERSON MATTHEW , DADI PRASANNA , BUTTERWORTH REGAN B. , JACOBSON DAVID
Published: June 2020

Tetraspanin7-mediated inhibition of β-cell voltage-dependent Ca2+ channels regulates glucose-stimulated insulin secretion.

Glucose-stimulated insulin secretion (GSIS) is regulated by Ca2+ influx into pancreatic β-cells through voltage-dependent Ca2+ channels (VDCCs). As some tetraspanin (TSPAN) transmembrane proteins control Ca2+ handling they may also modulate GSIS. TSPAN7 is the most abundant TSPAN in mouse and human islets. TSPAN7 autoantibodies are also found in type 1 diabetic serum, suggesting a link between TSPAN7 and diabetes. The aim herein was to determine if TSPAN7 controls β-cell Ca2+ handling and insulin secretion. Immunofluorescence imaging of mouse and human pancreatic slices indicated that TSPAN7 is highly expressed in β- and α-cells. shRNA-mediated TSPAN7 knockdown (KD) in mouse and human β-cells augmented glucose-stimulated Ca2+ influx (by 32.3±9.5% and 33.8±15.1% respectively) as well as KCl-stimulated Ca2+ influx (45 mM; 34.5±9.6%, human). Mouse β-cell Ca2+ oscillation frequency was also accelerated by TSPAN7 KD (by 29.4±10.1%). As TSPANs interact with and regulate VDCCs, we examined the effect of TSPAN7 on VDCC currents. TSPAN7 KD increased peak L-type VDCC currents in mouse and human β-cells (by 4.1±1.3 pA/pF and 2.0±0.9 pA/pF respectively). Heterologous expression of TSPAN7 with L-type VDCCs in HEK293 cells also decreased VDCC currents (CaV1.2: 4.3±1.8 pA/pF; CaV1.3: 17.5±5.4 pA/pF) and reduced KCl-stimulated (50 mM) Ca2+ influx (CaV1.2: 51.0±7.1%; CaV1.3: 28.4±7.5%). Furthermore, TSPAN7 coimmunoprecipitated with CaV1.2 and CaV1.3 from primary human β-cells and when heterologously expressed in HEK293 cells. Finally, TSPAN7 KD in human β-cells increased basal (5.6 mM glucose; 8.3±5.5 ng*hr-1) and stimulated (45 mM KCl+14 mM glucose; 20.4±17.1 ng*hr-1) insulin secretion. These findings reveal that TSPAN7 modulation of β-cell L-type VDCCs limits glucose-stimulated Ca2+ influx and insulin secretion.

Disclosure

M. Dickerson: None. P. Dadi: None. R.B. Butterworth: None. D. Jacobson: None.

Funding

American Diabetes Association (1-17-IBS-024 to D.J.); National Institutes of Health (T32DK101003, DK097392, DK115620); Vanderbilt University Medical Center Diabetes Research and Training Center (P60DK20593)
2108-P: Complex Posttranslational Processing of Glucagon Prohormone in Human Pancreatic Islets
Authors: ROMANOVA ELENA V. , RUBAKHIN STANISLAV , SWEEDLER JONATHAN V.
Published: June 2020

An array of signaling peptides and peptide hormones in pancreatic islets results from posttranslational processing of precursor proteins by well-characterized endopeptidases. While the encoded peptide complement can be predicted in silico from the prohormone sequence, actual peptide products often are more diverse due to additional chemical or enzymatic modifications of mature predicted peptides. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for comprehensive molecular characterization, we compiled an experimentally deduced database of endogenous peptides in human pancreatic islets and revealed an unexpected complex processing of several prohormones including proglucagon. Live pancreatic islets from several donors were provided by the Human Pancreas Analysis Program, University of Pennsylvania. Total of 2034 chemically unique peptide sequences were identified and matched to 477 proteins in the human protein database. Among interesting observations, we find differential cleavage of the signal peptide on the glucagon precursor protein, NP_002045.1, and unusual further processing of its encoded mature peptides. Alternate signal peptide cleavage sites are confirmed by detection of both classical GRPP, R[21]-D[50], and its novel variant S[18]-D[50]. An amidated IP-2 D[131]-L[142] and an isoform of MPGF D[131]-D[178], missing the GLP-1 sequence were detected. Previously unreported N-terminus acetylation of glucagon, GLP-1, GLP-1 (7-36), and oxyntomodulin was detected. Novel peptides potentially resulted from variable processing of mature glucagon, GRPP, and oxyntomodulin at internal convention cleavage sites were characterized. New chemically unique peptides originating from proglucagon and documented in this study indicate a more complex posttranslational processing of proglucagon in human islets than previously thought. The finding expands opportunity for mechanistic studies on pathology, progression, and treatments of diabetes.

Disclosure

E.V. Romanova: None. S. Rubakhin: None. J.V. Sweedler: None.

Funding

American Diabetes Association/Pathway to Stop Diabetes (1-18-VSN-19 to J.V.S.)
2114-P: Quantification of GLP-1R Trafficking in Primary Beta Cells in Response to Different Ligands
Authors: GRAY SARAH M. , RAVN PETER , SLOOP KYLE , CAMPBELL JONATHAN , D’ALESSIO JONATHAN
Published: June 2020

The glucagon-like peptide 1 receptor (GLP-1R) is a class B G-protein coupled receptor that is insulinotropic in β-cells. Multiple endogenous and synthetic ligands exist for the GLP-1R and each ligand interacts with the receptor differently to produce specific activation of intracellular signaling pathways. Ligand binding typically induces receptor internalization, leading to either i) receptor degradation or ii) recycling to the cell membrane. We hypothesized that each specific GLP-1R ligand would produce a unique trafficking profile in primary β-cells. To test this hypothesis, we developed flow cytometry-based assay that can be utilized in primary dispersed mouse islets. First, we validated a GLP-1R antibody (GLP-1R-APC) for flow cytometry application. The GLP-1R-APC stained β-cells, but not α-cells, aligning with the reported expression pattern in islets. Post-sort analysis confirmed GLP-1R expression only in the GLP-1R-APC+ population. Finally, GLP-1R-APC did not stain any cell populations in GLP1R-/- islets. Next, we used this assay to quantify GLP-1R internalization in wild type β-cells. To induce internalization, we treated dispersed islets with either vehicle or a GLP-1R ligand for 30 minutes prior to antibody staining. After vehicle treatment, 90% of the β-cells stained GLP-1R-APC+. Treatment with either GLP-1 or exendin-4 reduced the number of GLP-1R-APC+ β-cells by 97 and 89%, respectively, suggesting near complete internalization of all GLP-1Rs. In contrast, treatment with the GLP-1R antagonist exendin-9 produced staining similar to PBS controls. Finally, we used image-stream technology, a combination of brightfield microscopy and flow cytometry, to visually confirm GLP-1R internalization. Here, vehicle-treated cells produced GLP-1R staining only on the cell membrane, which was nearly ablated by the treatment with a ligand.

In conclusion, we have developed an assay that allows for quantification of GLP-1R trafficking in primary mouse islets.

Disclosure

S.M. Gray: None. P. Ravn: Employee; Self; AstraZeneca. K. Sloop: None. J. Campbell: Research Support; Self; Eli Lilly and Company, Novo Nordisk Inc. Speaker’s Bureau; Self; Merck Sharp & Dohme Corp. D. D’Alessio: Advisory Panel; Self; Eli Lilly and Company. Consultant; Self; Intarcia Therapeutics. Research Support; Self; Ansh Labs, Eli Lilly and Company, Merck Sharp & Dohme Corp. Other Relationship; Self; Novo Nordisk A/S.
2120-P: The Protein Phosphatase M1K Connects Glucose Sensing to Protein Translation in Pancreatic Beta Cells
Authors: DELEYE YANN , HERRING JACOB , HESS KAVAN H. , LEININGER BRENNAN , MCGARRAH ROBERT W. , TESSEM JEFFERY S. , WHITE PHILLIP J.
Published: June 2020

The protein phosphatase m1K (PPm1K) dephosphorylates and activates the rate limiting enzyme in the branched-chain amino acid (BCAA) catabolism pathway, branched chain a-keto acid dehydrogenase (BCKDH). A common single nucleotide polymorphism upstream of the gene for PPm1K is associated with elevated circulating levels of BCAA and increased risk for development of type 2 diabetes; however, the function of PPm1K in the pancreatic beta cell has not been assessed. In line with our previous observations in liver, we found that increasing glucose concentrations in INS1 cells results in elevated expression of the ChREBP β isoform and lower PPM1K mRNA expression. SiRNA-mediated knockdown (KD) of PPm1K to levels achieved by glucose in INS1 cells lead to robust phosphorylation of the ribosomal protein S6 on its regulatory phosphosites ser235/236 and ser240/s244. Notably, this occurred absent any effect on the phosphorylation of the upstream proteins mammalian target of rapamycin (mTOR) or p70 S6 Kinase (S6K) and could not be reversed by inhibiting BCKDH phosphorylation with the small molecule, BT2. Thus Ppm1K appears to regulate S6 independently of mTOR, S6K, and BCKDH. Surface sensing of translation (SUnSET) studies revealed that the increase in S6 phosphorylation in PPm1K KD INS1 cells is associated with a 2-fold increase in protein translation rate. Accordingly, PPm1K KD increased both insulin content and glucose stimulated insulin secretion in INS1 cells. In line with the higher translation rate, PPm1K KD cells displayed signs of endoplasmic reticulum stress including increased expression of spliced xbp1 and Bip mRNA.

In conclusion, our data highlight a new role for PPm1K in pancreatic beta cells, as a mechanism connecting glucose sensing to protein translation via modulation of S6 phosphorylation.

Disclosure

Y. Deleye: None. J. Herring: None. K.H. Hess: None. B. Leininger: None. R.W. McGarrah: None. J.S. Tessem: None. P.J. White: None.

Funding

American Diabetes Association/Pathway to Stop Diabetes (1-16-INI-17 to P.J.W.)
2123-P: Targeted Deletion of Grb10 in Pancreatic ß-Cells Increases ß-Cell Mass via mTORC-Dependent Inhibition of Cell Dedifferentiation
Authors: ZHANG JINGJING , LIU FENG
Published: June 2020

Growth factor receptor-bound protein 10 (Grb10) is an adaptor protein that negatively regulates insulin and mTORC1 signaling. Grb10 is highly expressed in mouse islets, but its role in β-cells function remains unclear. Here we show that Grb10 is highly expressed in human islets and the expression levels of Grb10 are markedly induced in the islets of diabetic mice as well as aged humans. β-cell-specific knockout of Grb10 in mice increased β-cell mass, reduced apoptosis, and improved glucose-stimulated insulin secretion. Mechanistically, knockout of Grb10 in β-cells enhanced mTORC1 signaling and inhibited β-cell dedifferentiation, which could be blocked by rapamycin administration in vivo. Our findings revealed a mechanism by which the Grb10/mTORC1 axis regulates β-cell dedifferentiation and function. Identification of key regulators of β-cell dedifferentiation will shed new light on the development of effective therapeutic strategies for treating both type 1 diabetes (T1D) and type 2 diabetes (T2D).

Disclosure

F. Liu: None.

Funding

National Natural Science Foundation of China (91749118, 81770775, 81730022); Planned Science and Technology Project of Hunan Province (2017RS3015)