bluuebunny/crossref_metadata_2025_split huggingface dataset:
2062-P: Pancreatic Inflammation Implicates Increased Cellular Plasticity in the Pancreatic Duct Glands in Type 1 Diabetes
Authors: KULKARNI SHWETA S. , BUTLER ALEXANDRA E. , ATKINSON MARK A. 
Published: June 2020

Type 1 diabetes (T1D) is an autoimmune disease characterized by endocrine/exocrine pancreas inflammation, fibrosis and, ultimately, decreased organ mass. Accumulating evidence suggests that this chronic inflammation may play a pivotal role in the initiation and progression of endogenous pancreatic cell plasticity. Pancreatic duct glands (PDGs), a potential stem/progenitor cell niche, represent a distinct anatomical compartment of the pancreas, forming blind-ending outpouchings from the main pancreatic duct and its branches. PDGs become activated in response to inflammation in T1D, evidenced by a high frequency of epithelial cell replication and an increase in progenitor-like cells. We addressed the hypothesis that in T1D, perturbation of hormone and non-hormone expressing cells in the interlobular ducts (ILD) and PDGs is a consequence of inflammation. Pancreatic sections from 21 T1D (disease duration 3 - 84 y) and 22 age-matched nondiabetic (ND) donors were evaluated for replication and expression of known pancreatic endocrine hormones in ducts and PDGs. We confirmed increased duct and PDG replication in T1D (T1D vs. ND— ILD: 2.8 ± 0.9 vs. 0.7 ± 0.1%, p&lt;0.05; PDG: 3.4 ± 1.0 vs. 1.1 ± 0.4%, p&lt;0.05) and reduced frequency of insulin expressing cells (T1D vs. ND— ILD: 0.0 ± 0.0 vs. 0.4 ± 0.1%, p&lt;0.001; PDGs: 0.01 ± 0.01 vs. 0.8 ± 0.3%, p&lt;0.05). The frequency of PDG cell replication was highest in T1D donors with acute pancreatitis. No differences were found in the frequency of other endocrine cell types regardless of the presence of pancreatic inflammation. These data suggest that increased pancreatic ductal cell replication in the PDG compartment of subjects with T1D is associated with sustained autoimmunity-related inflammation. Efforts are underway to determine specificity of pancreatic ductal cell changes to islet or acinar inflammation and the identity of replicating ILD and PDG cells, to better understand the mechanisms underlying pancreatic ductal cell plasticity.

Disclosure
S.S. Kulkarni: None. A.E. Butler: None. M.A. Atkinson: None.
2074-P: Histone Deacetylase Inhibitors Improve Store-Operated Calcium Entry and Glucose-Stimulated Insulin Secretion in Cytokine-Stressed Pancreatic ß-Cells
Authors: LEE CHIH-CHUN , KONO TATSUYOSHI , WEAVER STACI A. , SOHN PAUL , EVANS-MOLINA CARMELLA 
Published: June 2020

Store-operated calcium entry (SOCE) is a mechanism that functions to refill endoplasmic reticulum (ER) Ca2+ stores in response to ER Ca2+ depletion, through gating of plasmallemal Ora channels by the ER Ca2+ sensor STIM1. Dysfunctional β cell SOCE has been observed in response to cytokine-mediated stress and in models of diabetes. To identify compounds capable of modulating SOCE, a screening was performed in INS-1 cells treated with interleukin-1β (IL-1β). Two HDAC inhibitors (HDACi), sodium butyrate (NaB) and MS275, rescued SOCE in a dose-dependent manner in IL-1β-treated INS-1 cells. While dysregulation of HDACs has been linked with metabolic disease, the relationship between HDACs and SOCE has not been tested in the pancreatic β cell. To this end, we explored the effect of HDACi on Ca2+ signaling, insulin secretion, and gene expression in cytokine-treated islets and β cells. In mouse islets treated with IL-1 β and interferon-𝛾;, NaB and MS275 increased first phase Ca2+ responses in response to glucose, while NaB restored glucose-induced Ca2+ oscillations. Consistent with this, NaB, but not MS275, restored GSIS in IL-1β-treated INS-1 cells and in human islets from donors with type 2 diabetes. Chronic (24 hrs) but not acute (8 hrs) HDACi treatment restored cytokine-mediated reductions in SOCE, raising the possibility that changes in gene expression may underlie these effects. To test this, qRT-PCR for SOCE molecular components was performed. Both NaB and MS275 restored STIM1 expression but had no effect on Orai1, Orai2 and Orai3 levels. Consistent with this, HDACi were unable to restore SOCE in IL-1β-treated STIM1 knockout INS-1 cells.
Taken together, these data suggest that HDAC inhibition restores insulin secretion under pro-inflammatory conditions through improved SOCE and upregulated STIM1 expression. Thus, our findings identify a novel pathway through which HDAC inhibition exerts protective effects in the diabetic β cell.

Disclosure
C. Lee: None. T. Kono: None. S.A. Weaver: None. P. Sohn: None. C. Evans-Molina: Consultant; Self; Bristol-Myers Squibb.

Funding
National Institute of Diabetes and Digestive and Kidney Diseases (2R01DK093954)
2075-P: Testing the First Selective Talk-1 Inhibitors for Their Ability to Improve ß-Cell Function in Diabetes
Authors: NAKHE ARYA Y. , DADI PRASANNA , WESTOVER DAVID , DAYS EMILY , DENTON JEROD , JACOBSON DAVID 
Published: June 2020

Insulin levels are inadequate to maintain euglycemia in patients with type-2 diabetes (T2D), which is due in part to perturbations in pancreatic ꞵ-cell Ca2+ homeostasis. TALK-1 K+ channels are key regulators of ꞵ-cell electrical excitability, Ca2+ handling and glucose-stimulated insulin secretion (GSIS). KCNK16, which encodes TALK-1 is the most abundant ꞵ-cell K+ channel transcript and also the most islet-restricted ion channel transcript. Furthermore, a nonsynonymous coding sequence polymorphism in KCNK16 causes a predisposition for developing T2D. However, the ability to utilize TALK-1 as a therapeutic target to normalize ꞵ-cell Ca2+ homeostasis in T2D has not been determined. Here, we optimized a high throughput fluorescence-based thallium (TI+) flux assay (z’ =0.64) to screen for TALK-1 inhibitors, which resulted in identification of 286 TALK-1 inhibitors with potent drug-like properties (from a 50,000 compound screen). Of these hits, 78 exhibit TALK-1 selectivity and do not influence the activity of other K+ channels including TALK-2, TREK-2, TASK-1, TASK-3, KATP or hERG channels. We then performed dose response curve analyses and identified 9 potent inhibitors with IC50s &lt; 2.5μM that inhibit TALK-1 activity (&gt;65%). To test the efficacy of the inhibitors for their ability to augment islet function, we assessed their impact on mouse islet Ca2+ handling. TALK-1 inhibitors significantly increased islet Ca2+ oscillation frequency (e.g., VU0233408, 2.47 peaks/min vs. DMSO, 1.82 peaks/min, p-value= 0.011), similar to what was previously observed in TALK-1 KO islets. Moreover, the inhibitors did not increase glucose-stimulated Ca2+ oscillation frequency in TALK-1 KO islets. Thus, pharmacological inhibition of TALK-1 is predicted to increase GSIS.
In conclusion, we have identified the first potent and selective TALK-1 inhibitors that can be utilized to assess the role of TALK-1 during human ꞵ-cell GSIS under physiological and diabetic conditions.

Disclosure
A.Y. Nakhe: None. P. Dadi: None. D. Westover: None. E. Days: None. J. Denton: None. D. Jacobson: None.

Funding
National Institute of Diabetes and Digestive and Kidney Diseases (R01DK115620VDC); Vanderbilt University Diabetes and Research Training Center (P60DK20593)
2078-P: APPL2 Deficiency Diminishes Glucose-Stimulated Insulin Secretion in Pancreatic Beta Cells
Authors: LIN HUIGE 
Published: June 2020

In response to elevated postprandial blood glucose, remodeling of F-actin enables exocytosis of insulin granules from pancreatic β cells. Dysregulation of F-actin remodeling contributes to defective glucose-stimulated insulin secretion (GSIS) in β cells and subsequent type 2 diabetes. The adaptor protein APPL1 potentiates GSIS and prevents β cell loss in diabetes, but the role of its close homolog APPL2 in β cell function remains unknown. Here we demonstrated that APPL2 controls GSIS by Rac1-mediated F-actin depolymerization via interaction with Rac GTPase activating protein 1 (RacGAP1). β-cell specific deletion of APPL2 induced defective GSIS and glucose intolerance in mice. Ex vivo study revealed a dramatic reduction in both first- and second-phase GSIS in islets, accompanied by a dysregulation of F-actin remodeling. Consistently, knockdown of APPL2 caused impaired glucose-induced F-actin remodeling and insulin secretion in INS-1E β cells. The defects were mainly due to the inactivation of Rac1- the key player controlling insulin granule secretion via F-actin remodeling. Ectopic expression of constitutively active Rac1 mutant rescued the defective GSIS and F-actin remodeling in APPL2 deficient β cells. Furthermore, we identified RacGAP1 as an interacting partner of APPL2. RacGAP1 interacted with and regulate activity of Rac1, and overexpression of RacGAP1 significantly suppressed glucose-induced F-actin depolymerization, whereas co-expression with APPL2 antagonized this suppressive effect. In addition, the defects in APPL2 knockdown β cells were largely reversed by simultaneous downregulation of RacGAP1 or co-expression of constitutively active Rac1 mutant.
In summary, our study suggest that APPL2 potentiates GSIS by antagonizing the inhibitory effect of RacGAP1 on Rac1 activation and F-actin remodeling and insulin secretion in β cells, highlighting the importance of APPL2 in the regulation of GSIS in pancreatic β cells and glucose homeostasis.

Disclosure
H. Lin: None.

Funding
National Natural Science Foundation of China (81970675)
208-LB: Stimulation of the ß3 Adrenergic Receptors Prime Human White and Brown Adipocytes for Increased Lipolysis and Thermogenesis
Authors: LEA HANNAH J. , ZHU KENNETH Y. , CERO CHERYL , CYPESS AARON M. 
Published: June 2020

Recent clinical trials show that chronic activation of the β3-adrenergic receptor (AR) by mirabegron leads to numerous beneficial physiological responses, including increased energy expenditure, insulin sensitivity, and improved lipoprotein profile. Preliminary evidence suggests that they are mediated in part through adaptations by adipose tissue, but little is known about how mirabegron affects the cellular metabolism of human white or brown adipocytes (hWA and BA, respectively). We therefore treated paired immortalized hWA and hBA for 6 hours with a range of mirabegron doses (1 nM - 10 µM), as well as the β1- and β2-AR selective agonists, dobutamine and terbutaline, at 10 µM. We found that in untreated cells, ADRB1 and ADRB2 were higher in hWA than hBA, but ADRB3 was higher in hBA. However, mirabegron at all concentrations increased the expression of ADRB3 in hWA, and the highest dose of mirabegron boosted expression above that in hBA. While an increase in ADRB3 was detected in hWA with β1- and β2-agonist treatment, no changes occurred to the other two β-ARs when exposed to their selective agonists. Downstream, the β1- and β2-agonists increased thermogenic UCP1 expression in hWA, but mirabegron raised UCP1 expression only in hBA. Among the genes associated with lipolysis, glucose metabolism, and insulin signaling, mirabegron 10 µM promoted the expression of ATGL and HSL encoding genes, as well as GLUT4 in hBA only. In contrast, no changes occurred in hWA.
In summary, chronic exposure to a β3-AR agonist primes human white adipocytes to respond more potently to adrenergic-mediated lipolysis and enables human brown adipocytes to increase their thermogenic capacity.

Disclosure
H.J. Lea: None. K.Y. Zhu: None. C. Cero: None. A.M. Cypess: None.
2083-P: Dynamics of D-Amino Acids in Mammalian Pancreatic Islets
Authors: LEE CINDY J. , PATEL AMIT , LEE DONGKYU , RUBAKHIN STANISLAV , SWEEDLER JONATHAN V. 
Published: June 2020

Evidence has shown the presence of D-amino acids (D-AAs), unusual cell-to-cell signaling molecules, in the pancreatic islets of rodents and humans. In particular, D-alanine (D-Ala) and serine racemase, the enzyme that converts L- to D-serine (D-Ser), colocalize within insulin-producing beta cells. Both D-Ala and D-Ser function as co-agonists of the N-methyl-D-aspartate (NMDA) receptor, which is also present in islets and modulates insulin release, suggesting potential autocrine or paracrine signaling role of these compounds. Here, we investigated the relationship between the endogenous levels of D-AAs and islet regulation of glucose homeostasis. The glucose-stimulated D-AA profiles in the rat islets revealed that the L-AA forms were released from the pancreatic islets in a dose-dependent manner. Interestingly, we observed between a 20% and 45% reduction of D-Ala and D-Ser levels, respectively, in islets after the stimulation which appears to be independent of the extracellular glucose levels. In addition to islets, significant D-AAs were detected in the surrounding acinar tissue; only D-Ala was abundant at high percentage of 11.6 ± 1.5% to total Ala in the tissue, while other D-AAs were not measured at high levels. As beta cells appear not to be able to synthesize their own D-Ala, this suggests that the D-Ala detected in these cells can be supplied by nearby acinar tissue. We also have measured the D-Ser percentages in healthy and type 2 diabetes (T2D)-affected islets received from the Human Pancreas Analysis Program (UPenn). Preliminary results revealed the lower D-Ser level in the T2D-affected islets compared to healthy islets. We are continuing to accumulate more data to determine the potential correlation of D-AAs, including D-Ala and D-Ser, to diabetes progression. The continued characterization of endogenous D-AAs levels will shed light on their roles in islet normal and pathological functions.

Disclosure
C.J. Lee: None. A. Patel: None. D. Lee: None. S. Rubakhin: None. J.V. Sweedler: None.

Funding
American Diabetes Association/Pathway to Stop Diabetes (1-18-VSN-19 to J.V.S.)
2087-P: Functional Genomics of Human Islet Gluco/Lipotoxicity and Type 2 Diabetes
Authors: YI XIAOYAN , MARSELLI LORELLA , PIRON ANTHONY , SULEIMAN MARA , SZYMCZAK FLORIAN , EIZIRIK DECIO L. , MARCHETTI PIERO , CNOP MIRIAM 
Published: June 2020

Gluco- and lipotoxicity impair β cell function and survival, potentially contributing to type 2 diabetes onset and progression. Here we profiled transcriptomes of human islets in gluco/lipotoxic and type 2 diabetes conditions. Human islets from 26 nondiabetic donors were exposed to 0.5 mM palmitate (P), 22.2 mM glucose (G), P+G, 1 mM palmitate+oleate, (1:2 ratio, P+O) and P+O+G for 2 days (n=2-5/condition), followed by 4 days of washout. Glucose-stimulated insulin secretion and RNA-seq transcriptomes were assessed. Data were compared to RNA-seq of islets from 34 type 2 diabetic and 62 nondiabetic donors by rank-rank hypergeometric overlap (RRHO), and to the Connectivity Map to identify therapeutic targets. PO did not impair insulin secretion, P or G induced transient dysfunction (resolved after washout), while PG or POG induced persistent β cell dysfunction. Among common upregulated pathways in lipo- and gluco/lipotoxicity were PPAR signaling, protein processing in the endoplasmic reticulum and aminoacyl tRNA biosynthesis (gene set enrichment analysis). The greatest overlap by RRHO between upregulated genes in gluco/lipotoxicity and type 2 diabetes was seen for washout of PG and POG (conditions of persistent β cell dysfunction), with gene set enrichment for inflammatory responses and extracellular matrix organization. Comparison of gluco/lipotoxic and type 2 diabetes gene signatures with the Connectivity Map identified endoplasmic reticulum stress signaling and knockdown of the cholesterol sensor SCAP as strongly positively correlated pathways. A negative correlation was found for JNK and DNA protein kinase inhibitors, pointing to compounds that could revert gluco/lipotoxic and type 2 diabetes gene expression signatures.
In conclusion, human islet transcriptome signatures of transient or persistent gluco/lipotoxicity identify similarities to type 2 diabetes islet transcriptomes and point to novel therapeutic targets.

Disclosure
X. Yi: None. L. Marselli: None. A. Piron: None. M. Suleiman: None. D.L. Eizirik: None. P. Marchetti: Consultant; Self; Menarini Group. Research Support; Self; Janssen Pharmaceuticals, Inc. M. Cnop: None.
2094-P: Effects of Irisin on Human Pancreatic Islets from Type 2 Diabetic Subjects
Authors: MARRANO NICOLA , NATALICCHIO ANNALISA , BIONDI GIUSEPPINA , CIGNARELLI ANGELO , VINCENTI LEONARDO , LUPO LUIGI G. , PERRINI SEBASTIO , LAVIOLA LUIGI , GIORGINO FRANCESCO 
Published: June 2020

Irisin is a hormone secreted by skeletal muscle following physical activity and excess of saturated fatty acids, able to improve metabolic homeostasis and promote energy expenditure. In a previous study, we have demonstrated that, in beta-cells, irisin promotes proliferation and glucose-stimulated insulin secretion (GSIS), increases insulin content levels, and reduces lipotoxicity-induced apoptosis. The aim of this study was to evaluate the effects of irisin on the function and survival of pancreatic islets isolated from patients with type 2 diabetes mellitus (T2DM), characterized by reduced ability to secrete insulin and high levels of apoptosis, and to investigate the molecular mechanisms underlying this action. Pancreatic islets isolated from T2DM patients (n=7) and nondiabetic subjects (ND) (n=3), as well as INS-1E cells, were exposed to 100 nM irisin for different times. GSIS, insulin content, apoptosis and cytoplasmic calcium levels were measured by ELISA assays; the activation of the main mediators of beta-cell intracellular signalling (AKT, CREB and PKA) was evaluated by immunoblotting. Irisin increased GSIS approximately 2-fold (p&lt;0.05) in both ND and T2DM islets. Notably, in T2DM islets, characterized by reduced GSIS, this was restored to the levels of ND islets. In addition, irisin increased insulin content (1.6-fold in ND, 1.9-fold in T2DM, p&lt;0.05) and tendentially decreased apoptosis levels only in T2DM islets. Moreover, irisin was able to activate AKT and CREB under conditions of high glucose in the ND islets, without changing cytoplasmic calcium levels. In contrast, in the T2DM islets, irisin did not induce AKT or CREB activation.
In conclusion, the myokine irisin is able to increase the secretory function and survival of human pancreatic islets and to improve the functional defects typical of the T2DM islets. The mechanisms underlying the secretagogue effects of irisin in the T2DM islets do not apparently involve the known signaling machinery of this novel hormone.

Disclosure
N. Marrano: None. A. Natalicchio: Consultant; Self; AstraZeneca, Novo Nordisk Inc., Sanofi-Aventis. G. Biondi: None. A. Cignarelli: None. L. Vincenti: None. L.G. Lupo: 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
European Union (AIM1810057)
2099-P: Combined Proteomics and Lipidomics Studies Uncovered New Molecular Alterations Underlying Beta-Cell Glucotoxicity
Authors: WOODS JAMES , PAN BO , CHEN XUEQUN 
Published: June 2020

In T2D, chronic hyperglycemia causes beta cell dysfunction and failure. To systematically characterize the molecular alterations underlying this detrimental process, quantitative proteomic studies were carried out to compare global protein changes in INS-1 832/13 cells in normal (11mM) or high glucose (HG, 25mM) for 48 hours. In parallel, untargeted lipidomic studies were carried out to compare global lipid changes. In four experiments, a total of 4088 proteins were quantified, among which 184 proteins were significantly altered upon HG treatment. While we have confirmed some known hallmark changes (e.g., PDX1 and insulin) in beta cell glucotoxicity, most of these protein changes have not been reported previously. These proteins involve in key biological processes such as cell cycle regulation, calcium homeostasis, insulin biogenesis, protein folding, and ER export. Consistent with the significantly increased triglycerides in the lipidomic study, fatty acid synthase and acetyl-CoA carboxylase, two key enzymes in fatty acid synthesis, were significantly upregulated. In addition, for the first time in beta cells, MIG12 was found highly upregulated (4.50±1.50, n=4) in HG treated cells. This change was confirmed by Western blotting in mouse and human islets. MIG12 was previously reported in the liver to induce ACC1 polymerization and enhance its enzymatic activity. However, its role in beta cell is unknown. Our preliminary results showed that MIG12 knockdown inhibited HG-induced lipid droplet formation in beta cells. Among other novel findings, ether lipids and its regulating enzymes were significantly altered. This lipid change was confirmed by thin layer chromatography, and the enzyme change confirmed by Western blotting in beta cells and immunofluorescence in db islets. Functional consequences of several key protein changes are being investigated. Taken together, our study provides new targets for mechanistic studies of beta cell glucotoxicity.

Disclosure
J. Woods: None. B. Pan: None. X. Chen: None.

Funding
National Institutes of Health (R01DK110314)
21-LB: Derived Time-in-Range Is Associated with MACE in T2D: Data from the DEVOTE Trial
Authors: BERGENSTAL RICHARD M. , HACHMANN-NIELSEN ELISE , KVIST KAJSA , BUSE JOHN B. 
Published: June 2020

Background: There is a need to validate time-in-range (TIR; percentage of time with plasma glucose between 70 and 180 mg/dL (3.9-10.0 mmol/L) as a surrogate endpoint for long-term clinical outcomes.
Methods: We used data from patients with 8-point glucose profiles (8pp) from the double-blind cardiovascular outcomes trial, DEVOTE (NCT01959529). In total, 7637 patients with T2D and either established CVD or at high risk for CVD were included in the trial. The primary endpoint in DEVOTE was time to first MACE. The 8pp were collected at 1 year, 2 years and end-of-trial. Median length of follow-up was 2 years. For 5644 patients, 8pps with at least 7 points existed. Among the 681 major adverse cardiovascular events (MACEs) in DEVOTE, 360 were among patients with 8pps. Individual TIR was derived as the proportion of the 8pp within range. A Cox model was used to estimate the association between derived TIR and time to first MACE. Hazard ratios (HR) were estimated for patients with TIR&gt;70% vs. TIR≤70%, and for TIR&gt;70% and TIR 50 −70% vs. TIR≤50%.
Results: Derived TIR was &gt;70% for 65% of the patients. Estimated rate of first MACE was lower for TIR &gt;70% and TIR 50-70% vs. TIR≤50% (Figure) and for TIR&gt;70% vs. TIR≤70% (HR: 0.74 [0.60;0.91]95% CI; p&lt;0.01). The associations were maintained when analyses were adjusted for baseline characteristics.
Conclusions: Derived TIR was associated with rate of first MACE for T2D patients in DEVOTE.

Disclosure
R.M. Bergenstal: Consultant; Self; Ascensia Diabetes Care, Johnson & Johnson. Other Relationship; Self; Abbott, Dexcom, Inc., Hygieia, Lilly Diabetes, Medtronic, Novo Nordisk A/S, Onduo, Roche Diabetes Care, Sanofi, UnitedHealth Group. E. Hachmann-Nielsen: Employee; Self; Novo Nordisk A/S. K. Kvist: Employee; Self; Novo Nordisk A/S. J.B. Buse: Consultant; Self; Cirius Therapeutics, CSL Behring, Neurimmune. Research Support; Self; American Diabetes Association, National Institutes of Health, Novo Nordisk A/S, Patient-Centered Outcomes Research Institute, Sanofi, Tolerion, Inc., vTv Therapeutics. Stock/Shareholder; Self; Mellitus Health, Pendulum Therapeutics, PhaseBio Pharmaceuticals, Inc., Stability Health. Other Relationship; Self; ADOCIA, AstraZeneca, Dance Biopharm Holdings, Inc., Eli Lilly and Company, MannKind Corporation, NovaTarg Therapeutics, Novo Nordisk A/S, Senseonics, Inc, vTv Therapeutics, Zafgen, Inc.

Funding
Novo Nordisk A/S