bluuebunny/crossref_metadata_2025_split huggingface dataset:
2079-P: Racial Differences in Gut Microbiota, ß-Cell Function, Body Fat Distribution, and Their Relation with Incretins in Subjects with Normal Glucose Tolerance
Authors: NIZIGIYIMANA PAUL , LIU LERONG , XU BOYA , LIU TINGTING , GAO LIN , LIU ZEHAO , LI CHANGJUN , LUO XIANGHAN , LEI MINXIANG 
Published: June 2020

Racial differences in the gut microbiota and its influence in development of diabetes have been previously reported. However, whether differences exist between Chinese and Africans, currently no study. We investigated whether differences in body fat may account for microbial communities to expound racial disparities in insulin secretion, sensitivity or resistance, and that GLP-1 may play a role. We measured fasting and stimulated GLP-1, insulin and glucose levels during a 3h OGTT in 27 Han-Chinese university students(HC) and 29 International students from East Africa(EA) healthy subjects with normal glucose tolerance. We also measured the whole body fat and the regions of interest of local body composition, and gut microbiota composition. HC group showed significantly higher triglyceride levels, total bile acids, glucose response at 30min, incremental glucose level at 30min, HOMA-IR at 30 min, body fat distribution and abundance of microbial phyla, but lower hip circumference and β-cell function than EA. Interestingly, HC had lower bacterial taxa and majority of measures of microbial diversity than EA. GLP-1 correlated with metabolic risk factors and microbial communities. The results suggest that body fats are associated with gut microbiota and that GPL-1 enhances their association, which in turn may result in Chinese developing T2DM.

Disclosure
P. Nizigiyimana: None. L. Liu: None. B. Xu: None. T. Liu: None. L. Gao: None. Z. Liu: None. C. Li: None. X. Luo: None. M. Lei: None.
2089-P: Islet GLUT2 Plasticity Improves Glycemic Control in Insulin-Resistant KK Mice but Not T2DM KKAy Mice
Authors: LEPARD KATHY J. , SONDGEROTH KORIE L. 
Published: June 2020

Beta cells secrete insulin in response to glucose entry by GLUT transporters. GLUT are reduced in beta cells from T2DM rodents. We hypothesized that glucose entry into islets would be reduced in T2DM mice. Islets were isolated from euglycemic mice (C57/Bl6, ICR), insulin-resistant but euglycemic mice (4 and 8 wk KK), prediabetic mice (4 wk KKAy), and T2DM mice (8 wk KKAy). Islets were exposed to the fluorescent glucose analogue 2-NBDG in presence or absence of high glucose or the GLUT inhibitor phloretin. Islet fluorescence was visualized using confocal microscopy and quantified from 3-D images using FIJI Image J. GLUT2 protein was determined in isolated islets by ELISA. Islet GLUT2 location was determined using IF sections with blinded observers assigning a score from 0 (cytosol) to 10 (cell membrane). *p&lt;0.05. Using islets from euglycemic mice, 2-NBDG entry was competitively reduced 59% by high glucose and 30% by phloretin. Despite a 44% decrease in islet GLUT2 protein in prediabetic mice (KK, 4.0±0.5; KKAy, 2.3±0.3*), 2-NBDG entry into islets was similar (KK: 7.32±0.86; KKAy: 7.25±0.86). More GLUT2 transporters were located in the membrane of islets from KKAy (5.88±2.14*) as compared to KK (4.44±3.06) mice. Phloretin significantly decreased 2-NBDG entry in both KK (6.31±0.61*) and KKAy (6.52±0.69*) mice. By 8 wks of age, islet GLUT2 protein had decreased by 51% in KK mice (1.97±0.50*) with no change in KKAy mice (2.58±0.22), yet 2-NBDG entry was not altered (KK: 7.32±0.63; KKAy: 7.35±0.62). More GLUT2 was located in the membrane of 8 wk KK (7.08±1.68*) as compared to 4 wk KK mice. Membrane GLUT2 was unchanged in KKAy mice. Phloretin increased 2-NBDG entry into islets from both KK (8.05±0.48*) and KKAy (7.95±0.79*) mice. With age, HbA1c did not change in KK mice (4.53-4.97%) but increased in KKAy mice (5.27-6.57%). Plasticity in islet GLUT2 content, location and transport was evident in islets from KK mice but not KKAy mice. Plasticity may contribute to better glycemic control in aging KK mice.

Disclosure
K.J. LePard: None. K.L. Sondgeroth: None.

Funding
Midwestern University (to K.J.L.)
2092-P: Invalidation of GSK3B in Pancreatic Beta Cell as a Therapeutic Target for T2D
Authors: MURRAY SUE , ZHANG JIANGWEI , FERNG ANNIE , PRAKASH THAZHA , LEE RICHARD , ANDERSSON EVA-MARIE , JANZÉN DAVID , KNERR LAURENT , AMMALA CARINA , GUO SHULING 
Published: June 2020

Insufficient pancreatic β-cell mass or function is one of the main causes underlying diabetes mellitus. Glycogen synthase kinase 3 (GSK3) is a ubiquitously expressed serine/threonine kinase. GSK3 is encoded by two known genes, GSK3 alpha (GSK3A) and GSK3 beta (GSK3B), and small molecule inhibitors targeting both are known to induce micronucleation. Isoform specific small molecule inhibitors targeting GSK3B have demonstrated increased cell proliferation and expansion of islets mass in human and rodents. However, many of the inhibitors target dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) in addition to GSK3B making the data difficult to interpret (Shen et al, Nature comms 2015). Mice with β-cell overexpression of GSK3B have reduced β-cell mass and proliferation through modulation of PDX-1 stability. Recently, Ämmälä et al. demonstrated conjugation of ASOs to glucagon-like-peptide-1 receptor (GLP-1R) ligand can productively deliver ASO cargo to the insulin secreting β-cells. The doses needed for GLP-1-conjugated ASOs to silence target genes in the β-cells are below what is needed to affect target gene expression elsewhere allowing for evaluation of specific inhibition in the β-cells. In lean C57B6 mice a single administration of GLP-1-conjugated GSK3B ASO achieved an ED50=0.016µmol/kg with no change to DYRK1A RNA expression. Here we demonstrate robust, specific GSK3B reduction in the β-cells after GLP-1-conjugated GSK3B ASO treatment in db/db mice. In contrast to the SMI data, specific inhibition of GSK3B in β-cells worsened the health based on reductions in β-cell specific genes, PDX1 and MAFA, and decreased the β-cell mass (2.9 ± 1.3mg GLP-1-Con ASO vs. 1.4 ± 0.6mg GLP-1-GSK3B ASO). In addition, no effect on glucose or insulin was observed suggesting specific inhibition of GSK3B in the β-cell is not enough to preserve the function and increase β-cell survival.
In summary, we have invalidated GSK3B as a therapeutic target for protecting the β-cell against glucotoxicity and T2D.

Disclosure
S. Murray: Employee; Self; Ionis Pharmaceuticals. J. Zhang: None. A. Ferng: None. T. Prakash: None. R. Lee: Employee; Self; Ionis Pharmaceuticals, Inc. E. Andersson: Employee; Self; AstraZeneca. Stock/Shareholder; Self; AstraZeneca. D. Janzén: None. L. Knerr: None. C. Ammala: None. S. Guo: Employee; Self; Ionis Pharmaceuticals, Inc.
2095-P: ß-Cell Glucose-Dependent Insulinotropic Polypeptide Receptors Are Necessary for Improved Islet Function following Sleeve Gastrectomy
Authors: DOUROS JONATHAN D. , CAMPBELL JONATHAN , TONG JENNY , D’ALESSIO DAVID 
Published: June 2020

Bariatric surgeries improve glucose control in part by enhancing the glucose sensitivity of insulin secretion. In a mouse model of sleeve gastrectomy (SG), prandial secretion of the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are increased and positively correlated with ex vivo insulin secretion. However, several previous studies suggest that GLP-1 action is dispensable for the effects of SG on glucose homeostasis. Therefore, we hypothesized that improved glucose control and islet function after SG require β-cell GIP receptors (GIPR). We tested this hypothesis using an inducible, β-cell specific GIPR knockout mouse line (GIPRβcell-/-). Within two weeks of surgery control mice with SG have reductions of bodyweight and glucose excursion during either a mixed-meal (MMTT) or intraperitoneal glucose tolerance test (IPGTT) compared to sham-operated animals. Islets isolated from control SG mice have enhanced glucose stimulated insulin secretion (GSIS) compared to islets from sham-operated controls in perifusion experiments, similar to our previous reports. While GIPRβcell-/- mice given SG evince improvements in bodyweight and MMTT glucose disposal compared to sham operated GIPRβcell-/- animals, they do not display the postoperative improvement of IP glucose tolerance seen in control mice given SG. Moreover, islets from GIPRβcell-/- SG mice do not have the improved GSIS typical of this surgery. These data indicate that changes in bodyweight and prandial glucose homeostasis after SG are not dependent on GIPR signaling. However, β-cell GIPR are necessary for enhancing intrinsic islet function after SG. These results support enteroendocrine signaling as a mediator for one of the key components of metabolic improvement after bariatric surgery.

Disclosure
J.D. Douros: None. J. Campbell: Research Support; Self; Eli Lilly and Company, Novo Nordisk Inc. Speaker’s Bureau; Self; Merck Sharp & Dohme Corp. J. Tong: None. 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.

Funding
1F32DK115031-01
210-LB: Combined Use of Oral Standard Cookie Meal (OSC) and the Newly Revised Insulin Suppression Test for the Evaluation of Whole Body (WB), Muscle, and Hepatic Glucose Clearance (GC) Under Endogenous or Exogenous Insulin and Its Clinical Usefulness
Authors: HARANO YUTAKA 
Published: June 2020

Adequate insulin action (sensitivity: IS) in muscle, liver and WB is the most important metabolic factor in diabetes, especially in S-GLUT-2 user. Oral intake of hypoglycemic agents followed by the standard 75g starch including 15% maltose (OSC, Saraya Co.), which is digested and absorbed into blood glucose at a constant rate for 2 hours, minus urinary glucose loss, divided by the steady state PG at 2h equals the GC in WB under the endogenous insulin secretion. In SGLUT-2 user(HbA1c, 6.8%, BMI, 25.3), this was significantly low(4.2±0.5,SE ml/kg/min, n=6 vs. normal, 8.7,n=10). Average of 1 and 2h insulin was low,10.5 vs. normal,30μU/ml. They are recommended to keep BMI below 23, upper normal range of IS, and use GLP-1 analog or insulin to compensate insufficient IS. This approximation is further evaluated using the revised half dose of glucose and insulin infusion, 3mg, 0.39mU/kg/min, with octreotide 50μg SC for muscle, 100μg for whole body, 30min before the test. Under this exogenous insulin(19.1μU/ml, at 2-4h), 2h GC is confirmed significantly low (2.3±0.1,n=6 vs. control, 3.7±1.0, n=10) reflecting impaired muscle GC in SGLUT-2 user. Additional intake of OSC under continued subcutaneous insulin(1.5 rate over iv), gives the 2h decreased GC (5.84, vs. normal, 9.5,) of WB, and the difference corresponding to hepatic GC, which was significantly low. Better GC was obtained for non-SGLUT groups on oral agents with or without insulin secretagogues. Conclusion Combined use of OSC and simplified IS test enables to evaluate muscle, hepatic and WB glucose utilization under endogenous or exogenous insulin. The method is useful to detect and clarify the various mechanisms of insulin resistance in diabetes, metabolic syndrome, heart failure, Alzheimer disease or fatty liver, etc.

Disclosure
Y. Harano: None.
2102-P: Regulation of Alpha-Cell Function by Beta-Cell Extracellular Vesicles
Authors: KALIVARATHAN JAGAN , SARAVANAN PRATHAB BALAJI , LEVY MARLON F. , KANAK MAZHAR A. 
Published: June 2020

People with severe type 1 diabetes (T1D) are known to experience life-threatening hypoglycemic events as a result of alpha cell dysfunction. The phenomenon that causes α cell dysfunction is still unclear. It has been reported that β-cells regulate α cells via paracrine signaling but the underlying mechanism still remains elusive. Extracellular vesicles (EVs) are a class of small vesicles (30-2000nm) that contain a variety of biomolecules. α and β-cells in the islets have been shown to release EVs. It is hypothesized that β-cells transfer signals via EVs in order to regulate α-cell function. Loss of β-cells results in a lack of exosomal communication that causes α-cell dysfunction. Here, we investigated the role of β-cell EVs in modulating α cell function. Mouse TC1-α and βTC6 cell lines were stimulated with low and high glucose media for 24h after exosome depletion. EVs were isolated from conditioned media using differential centrifugation methods. EVs were characterized using TEM, NTA analysis, confocal microscopy, and blotting for surface markers. Alpha cells were challenged with low and high glucose conditions in the presence or absence of EVs from β- cells in order to evaluate the role of EVs in glucagon secretion. ELISA was used to measure glucagon levels in the media, q-PCR was performed on glucagon and other regulatory genes such as MafB and c-Maf. The size of EVs based on NTA analysis was found to be 50 - 200nm. Confocal images reveal that the uptake of BODIPY labeled β-cell EVs after 3h was found localized in the nucleus and cytoplasm of α-cells. Under low glucose stimulation, mRNA and protein expression of glucagon in α-cells was significantly increased in the presence of β-cell EVs (6h: P = 0.0134). Expression of mafB which is a regulator of glucagon transcription correlated with glucagon expression. These results suggest a putative role of β-cell EVs in regulating α-cell function. Our findings will aid in developing new approaches for preventing severe hypoglycemic episodes by reversing α-cell dysfunction in T1D.

Disclosure
J. Kalivarathan: None. P. Saravanan: None. M.F. Levy: None. M.A. Kanak: None.
2110-P: Correlation between Ex Vivo Islet Proteomic Analysis and In Vivo Secretory Function in Humans
Authors: ASSUNTA CEFALO CHIARA MARIA , MEZZA TERESA , CINTI FRANCESCA , MOFFA SIMONA , CAPECE UMBERTO , KULKARNI ROHIT , GIACCARI ANDREA 
Published: June 2020

Insulin resistance and β-cell dysfunction are the main actors in the pathogenesis of type 2 diabetes mellitus, causing both quantitative and qualitative loss of insulin secretion and therefore hyperglycemia. The molecular mechanisms underlying progressive β-cell dysfunction, however, are still unknown. In order to correlate changes in the insular proteome to different metabolic conditions in vivo, a mass spectrometry analysis was performed on human islets, extracted by Laser Capture Microdissection, from surgical samples of 14 subjects who underwent duodeno-cephalopancreasectomy, and previously studied through OGTT and mixed meal test. The subjects were classified based on glucose tolerance into normal (n: 7 NGT), intolerant (n: 5 IGT) and diabetic (n: 2 DM2). A first quantitative analysis showed about 150 proteins differently expressed in the 3 groups. Among these, a protein, SEL1L, which regulates the differentiation of pancreatic precursors in the endocrine line was significantly increased in IGT rather than DM2 and NGT subjects and was inversely correlated with β-cell glucose sensitivity (r = -0.81, p = 0.01). The TCPD protein, involved in the folding and transport of neosynthesized proteins, which progressively decreases from NGT to DM2, was inversely correlated with the AUC of glycemia during OGTT (r = 0.5, p = 0.04). Finally, the expression of IQAG1 which was significantly reduced in DM2 compared to the other groups, and implicated in GLP-1 induced insulin production was inversely correlated with insulin resistance evaluated using the HOMA-IR index (r = -0.70, p = 0.004). The results suggest that both insulin resistance and/or β-cell dysfunction in vivo are closely linked to the intrainsular proteome in diabetic subjects.

Disclosure
C. Cefalo: None. T. Mezza: None. F. Cinti: None. S. Moffa: None. U. Capece: None. R. Kulkarni: None. A. Giaccari: Speaker’s Bureau; Self; Amgen, AstraZeneca, Eli Lilly and Company, Merck Sharp & Dohme Corp., Mundipharma, Novo Nordisk A/S, Sanofi-Aventis.
2111-P: Role of G-Protein Coupled Receptor 31 (GPR31) in ß-Cell Health and Disease
Authors: HERNANDEZ-PEREZ MARIMAR , HAIDER ISRA , ANDERSON RYAN M. , TERSEY SARAH A. , MIRMIRA RAGHAVENDRA 
Published: June 2020

Islet β-cell inflammation, dysfunction, and death are characteristic of diabetes. 12/15-Lipoxygenase (12/15-LOX) produces 12-HETE and is found activated under conditions of insulin resistance and systemic inflammation. 12-HETE acts as an inflammatory mediator that promotes β-cell dysfunction and death through oxidative stress. Since 12-HETE has been shown to bind the G-protein coupled receptor 31 (GPR31), we hypothesized that this binding activates pathways leading to β-cell dysfunction. To test our hypothesis, we screened primary islets and β-cell lines for the presence of GPR31 and studied islets and glucose homeostasis in Gpr31b-/- mice. We observed that GPR31 is present in human and mouse islets, and the mouse β cell-derived cell line (βTC3). Consistent with a role in inflammation, GPR31 expression was increased upon stimulation with a cocktail of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β). We also created a germline knockout of the gene encoding GPR31 (Gpr31b) in mice. Similar to mice with deletion of the gene for 12/15-LOX (Alox15-/-), Gpr31b-/- mice were viable and healthy, with body weight and glucose tolerance indistinguishable from control littermates. To mimic conditions of insulin resistance in vitro, we treated isolated islets Gpr31-/- and control littermates with 10 µM S961, an insulin receptor inhibitor. Treated control islets showed an expected decrease in β-cell identity genes (Ins1/2, Pdx1), genes encoding antioxidant enzymes (Gpx1), and an increase in genes associated with ER stress (Chop, sXbp1). In contrast, Gpr31b-/- islets expression of these genes was resistant to S961. Compared to control littermates, Gpr31-/- mice were resistant to glucose intolerance induced by the β-cell inflammatory toxin streptozotocin. Together these data support the hypothesis that the major product of 12/15-LOX, 12-HETE, acts via GPR31 in promoting β-cell dysfunction in the setting of insulin resistance and inflammation.

Disclosure
M. Hernandez-Perez: None. I. Haider: None. R.M. Anderson: None. S.A. Tersey: None. R. Mirmira: Advisory Panel; Self; Hibercell, Sigilon Therapeutics, Veralox Therapeutics. Employee; Spouse/Partner; Eli Lilly and Company.

Funding
JDRF (3-PDF-2019-750-A-N); National Institutes of Health (T32DK064466, R01DK105588, (P30DK097512)
2113-P: Discrepancy between Single-Cell RNA Sequencing and Protein Expression Assessments of GLP-1Rr Heterogeneity in Beta Cells
Authors: GRAY SARAH M. , CHAZOTTE BRYANNA M. , ROSS ELIZABETH C. , SVENDSEN BERIT , RAVN PETER , SLOOP KYLE , CAMPBELL JONATHAN , D’ALESSIO DAVID 
Published: June 2020

The glucagon-like peptide 1 receptor (GLP-1R) is insulinotropic in β-cells and the target of multiple classes of diabetes drugs. People with T2D secrete normal amounts of GLP-1, but are less responsive to its actions; the mechanisms for this are unknown. Studies have shown that metabolic stress decreases GLP-1R in islets, however, it is unknown if this occurs in all, or just a subset, of β-cells. We hypothesized that GLP-1R expression is heterogeneous in β-cells, such that not all β-cells express the GLP-1R, and that metabolic stress would decrease the number of GLP-1R+ β-cells. To test this, we first performed single-cell RNA sequencing (scRNAseq) in mouse and human islet cells and found that the majority of β-cells were GLP-1R negative, supporting significant heterogeneity. To validate the scRNAseq results, we generated a GLP-1R reporter mouse by crossing GLP-1R-Cre with mTmG mice. Using FACS to separate and qPCR to characterize positive (GFP+) from negative (tdTomato+) dispersed islet cells, we found GLP-1R+ cells were enriched for Ins2 and Sst, while GLP-1R- cells were enriched for Gcg, suggesting GLP-1R promoter activity is localized to β- and d-cells. In addition, β-cell markers were not present in the tdTomato+ population, suggesting very few GLP-1R negative β-cells. Next, we stained dispersed islets from the reporter mice with a validated GLP-1R antibody and found &gt;90% congruence with GFP+ cells and no staining in tdTomato+ cells. In dispersed islets from wild type mice, ∼90% of β-cells were GLP-1R+; very few of the α- or d-cells were GLP-1R+. Metabolic stress induced through chronic high-fat feeding or using multiparous models did not alter the number of GLP-1R+ β-cells.
In conclusion, assessment of GLP-1R expression and GLP-1R protein revealed the majority of β-cells are GLP-1R+, a finding that conflicts with the interpretation of scRNAseq data. These findings suggest caution in interpreting the results of scRNAseq for low abundant transcripts such as the GLP-1R.

Disclosure
S.M. Gray: None. B.M. Chazotte: None. E.C. Ross: None. B. Svendsen: 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.
2117-P: BET Bromodomain Inhibitors Mitigate Cytokine-Induced Transcription in ß-Cells via Inhibition of Nf-κB
Authors: NORD JOSHUA , WYNIA-SMITH SARAH , SMITH BRIAN C. 
Published: June 2020

Type 1 diabetes is an autoimmune disease characterized by chronic inflammation of pancreatic islets, mediated by proinflammatory cytokines, leading to reduced response to glucose and ultimately selective destruction of insulin-producing β-cells. In common with many autoimmune diseases, the exact causes are poorly understood. Although genetic predisposition is a factor, low concordance rates of autoimmune diabetes among monozygotic twins suggest an, as yet undetermined, contribution of epigenetic factors. Recent studies have begun to explore the contributions of epigenetic regulatory proteins in onset and progression of autoimmune diabetes. An important class of epigenetic “readers” is the bromodomain and extraterminal domain (BET) family (Brd2, Brd3, Brd4, and Brdt), which has emerged as promising drug targets for a wide variety of diseases. A unique trait of the BET family is that these proteins contain two bromodomains (BD1 and BD2) that afford them the capacity to simultaneously bind two acetylated histones and/or non-histone proteins such as DNA-binding factors to modulate transcription in a cell-type specific manner. Here, we use an insulinoma β-cell line (INS832/13) and primary rat islets to investigate the ability of chemical inhibitors of BET bromodomain proteins to decrease the β-cell response to proinflammatory cytokines. We found that BET inhibitors mitigated cytokine-induced transcription of inflammatory mediators known to damage β-cells. This is mediated through the inhibition of the NF-κB pathway by BET inhibitors. Furthermore, using CRISPR/Cas9 knockout insulinoma β-cell lines of Brd2, Brd3, and Brd4 and BD1 vs. BD2 specific chemical inhibitors, we identified key mechanisms through which this altered transcriptional profile occurs. This work provides important mechanistic insights to disease onset and progression of autoimmune diabetes for which current therapies are ineffective.

Disclosure
J. Nord: None. S. Wynia-Smith: None. B.C. Smith: None.

Funding
American Diabetes Association (1-18-IBS-068 to B.C.S.); National Institute of Diabetes and Digestive and Kidney Diseases (R01DK119359)