bluuebunny/crossref_metadata_2025_split huggingface dataset:
1730-P: In Vitro and In Vivo Effects of Increased IAPP Expression on Human Islet Function
Authors: WRIGHT JORDAN J. , JACKSON PAIGE B. , ARAMANDLA RADHIKA , DAVIS COREY , BRISSOVA MARCELA , POWERS ALVIN C. 
Published: June 2024

Introduction & Objective: Islet amyloid composed of islet amyloid polypeptide (IAPP) is often present in the pancreas in type 2 diabetes. Cell culture and transgenic rodent models have been used to study islet amyloid toxicity, but less is known about the effects of endogenously-produced IAPP on human islet function and health.
Methods: To evaluate acute and chronic effects of amyloid formation, we established a pseudoislet platform with adenoviral delivery of constructs expressing human IAPP (huIAPP) or mouse IAPP (moIAPP), which is not amyloidogenic. After 7 days in culture +/- exposure to the fatty acid palmitate, pseudoislets were evaluated for secretory function, islet structure and amyloid formation by ThioS staining. Pseudoislets were also transplanted into the anterior chamber of the eye of immunodeficient mice for assessment of secretory function for up to 3 months.
Results: After 7 days in culture, transduced pseudoislets had 6.3 fold greater cellular IAPP content than untransduced pseudoislets. HuIAPP expression resulted in greater amyloid formation (0.49 ± 0.12 vs 0.17 ± 0.07 % islet area), but no changes in insulin or glucagon secretion or cellular toxicity, compared with moIAPP pseudoislets. High resolution microscopy showed ThioS+ fibrils in the ER of huIAPP-expressing beta cells. No extracellular amyloid was seen. Exposure to 0.5mM palmitate for 3 days further increased amyloid deposition and impaired insulin secretion by huIAPP pseudoislets, but not moIAPP. HuIAPP pseudoislets transplanted into immunodeficient mice had normal insulin secretion after 4 and 8 weeks, but impaired secretion after 12 weeks, compared to moIAPP pseudoislets.
Conclusion: In vitro overexpression of IAPP in human pseudoislets induces intracellular amyloid formation, and in combination with lipotoxic stress, impairs insulin secretion. In vivo, human IAPP overexpression impairs insulin secretion after three months. This model will be valuable to elucidate mechanisms of islet dysfunction in type 2 diabetes.

Disclosure
J.J. Wright: None. P.B. Jackson: None. R. Aramandla: None. C. Davis: None. M. Brissova: None. A.C. Powers: None.

Funding
National Institutes of Health (K08DK133691); Veterans Administration (IK2BX005910)
1736-P: Exploring Intrinsic Features of Human Pancreatic a- and ß-Cell Physiology Using Pseudoislets
Authors: ROZO ANDREA V. , ROMAN JEFFEREY , QIN WEI , LIU CHENGYANG , NAJI ALI , KAESTNER KLAUS H. , HOSHI TOSHINORI , STOFFERS DORIS A. , DOLIBA NICOLAI M. 
Published: June 2024

Introduction: Mechanistic studies of pancreatic α- and β-cell physiology are challenging in whole islets due to interactions among different islet cell types. Reaggregation of sorted cell populations into pseudoislets offers the possibility to delineate the role of specific cell types, distinguish intrinsic cellular functions and paracrine interactions, and enhance accessibility for genetic interventions.
Methods: Building on methods of Walker et al, 2020, we generated &gt;90% enriched human α- and β-cell aggregates and studied hormone secretion by perifusion, mitochondrial function by Seahorse, Ca2+ flux by fluorescence imaging, and electrophysiology by whole-cell patch-clamp. Native islets and pseudoislets of dissociated unsorted islet cells served as controls.
Results: The native islet kinetics of insulin and glucagon responses to glucose were preserved in β- and α-cell aggregates, indicating direct effects of glucose; however, rates of secretion, adjusted for IEQ and cell proportion, were markedly lower compared to native islets and reaggregated controls, suggesting that optimal α- and β-cell function depends on other islet cell types. The primary stimulus of oxygen consumption rate (OCR) and Ca2+ flux in β- and α-cell aggregates was glucose and amino acids, respectively. Baseline OCR (no substrate) was higher in α- than β-cell aggregates. Electrophysiologically, both native islet and α-cell aggregate action potentials (APs) were larger in size and faster in kinetics than β-cell APs; however, high glucose-induced inhibition of α-cell APs and subsequent hyperpolarization observed in native islets and control reaggregates was noticeably impaired in α-cell aggregates, suggesting a role for other cell types in glucose-mediated inhibition of α-cells.
Conclusion: Cardinal features of α- and β-cell physiology are largely preserved in α- and β-cell enriched pseudoislets, establishing its feasibility in the study of intrinsic α- and β-cell physiology.

Disclosure
A.V. Rozo: None. J. Roman: None. W. Qin: None. C. Liu: None. A. Naji: None. K.H. Kaestner: None. T. Hoshi: None. D.A. Stoffers: Other Relationship; Eiger BioPharmaceuticals. N.M. Doliba: None.

Funding
National Institutes of Health (UC4DK 112217, U01DK123594)
1740-P: The Effects of SGLT2 Inhibitor Canagliflozin on Glucagon Secretion in SUR1 Knockout Mice
Authors: ZHANG TINGTING , HAN DONGNA , MENG SHI , LI RUYUE , LI CHANGHONG 
Published: June 2024

Studies have showed that some of SGLT2 inhibitors increased the release of glucagon. But the selective SGLT2 inhibitors, such as canagliflozin, don’t directly stimulate glucagon secretion due to its low SGLT1 potency. Congenital hyperinsulinism due to KATP channels loss-of-function mutations have suppressed glucagon secretion. We therefore applied canagliflozin to SUR1 knockout (SUR1-/-) mice to investigate if SGLT2i could affect glucagon secretion when both β- and α-cells are constantly depolarized. Single dose of canagliflozin (30 mg/Kg) were orally administered to wildtype mice (WT) and SUR1-/- mice, then followed by an oral glucose challenge. Glucose, insulin, and glucagon were measured. Glucagon secretion was also studied in isolated islets. Compared to vehicle controls, canagliflozin significantly lowered glucose levels and improved glucose tolerance in WT mice without altering insulin and glucagon secretion. Ratios of insulin and glucagon to glucose were unchanged after 30 min of glucose challenge. In SUR1-/- mice, canagliflozin did not affect glucose and insulin levels, but it significantly increased glucagon secretion. Canagliflozin also enhanced glucose tolerance in SUR1-/- mice with improved insulin/glucose ratio and elevated ratio of glucagon/glucose. In isolated islets, canagliflozin (10 µM) has no effects on amino acid mixture (AAM) stimulated glucagon secretion and glucose mediated suppression of glucagon secretion in WT islets. SUR1-/- islets are sensitive to AAM stimulated insulin secretion, but lack of glucose suppression of glucagon secretion, and canagliflozin does not change such pattern. However, canagliflozin induced a 2-fold increase of basal glucagon secretion in SUR1-/- islets. This study showed that when α-cells were depolarized by KATP channel deletion, canagliflozin stimulated glucagon secretion both in vivo and in isolated islets, suggesting that SGLT2 inhibitors have intrinsic effects on α-cells.

Disclosure
T. Zhang: None. D. Han: Employee; Nanjing Ascendrare Pharmaceutical Technology. S. Meng: Employee; Nanjing Ascendrare Pharmaceutical Technology. R. Li: Employee; Nanjing Ascendrare Pharmaceutical Technology. C. Li: Employee; Hua Medicine (Shanghai) LTD., Nanjing AscendRare Pharmaceutical Technology.

Funding
National Natural Science Foundation of China (82070802)
1758-P: Biased GPBAR Signaling in Regulating Islet Homeostasis and Glucose Metabolism
Authors: SUN JINPENG , YU XIAO , CHENG JIE , SHANG PAN 
Published: June 2024

Introduction & Objective: The bile acid membrane receptor GPBAR is an important drug development target for metabolic diseases. Previous studies have demonstrated that some bile acids and their analogues improve glucose metabolism homeostasis by activating GPBAR in vivo.
Results: We found that, in contrast to the endogenous ligand LCA, INT-777 exhibited a Gs-preference while P395 and OA exhibited a β-arrestin-2-bias. In the study, we selected natural product oleanolic acid (OA), bile acid analogue INT-777, endogenous bile acid and small molecule Gpbar agonist P395 to evaluate their effects in islets and found that INT-777 and P395 promoted glucose-stimulated insulin secretion at lower concentrations in pancreatic islets, while natural multiple bile acids as well as OA increased insulin secretion stimulated by high glucose only at high concentrations, as evidenced by Gpbar-/- mice. In an immune factor-induced islet inflammation model, low concentrations of INT-777 and P395 were shown to exert anti-inflammatory effects, while natural bile acids and OA required high concentrations to exhibit similar effects. Moreover, the ligands that displayed an obvious for Gs signaling, INT-777 and LCA could significantly inhibit the endoplasmic reticulum stress induced by thapsigargin, but P395 did not, which were evidenced by pdx1-cre+/-Gsfl/fl mice and Arrb2-/- mice.
Conclusion: These findings collectively indicated that ligands of GPBAR with Gs-biased viability, may could better improve islet homeostasis and provide a rational design of GPBAR-targeting drugs for diabetes or other metabolic diseases.

Disclosure
J. Sun: None. X. Yu: None. J. Cheng: None. P. Shang: None.
1763-P: ATF6 Drives Glucose-Dependent Beta-Cell Proliferation by Increasing E2F1 Expression and Activity
Authors: LANDA GALVAN HUGUET V. , CASTRO THALIA , NOEL JAHI J. , AVILA LLAMAS GABRIEL , SHARMA ROHIT B. , ALONSO LAURA C. 
Published: June 2024

Introduction and Objective: During elevated insulin demand, beta cells activate the Unfolded Protein Response (UPR); some also undergo proliferation. Activation of the ATF6 arm of the UPR induces beta cell proliferation, but only in high glucose. We aimed to identify the mechanism by which ATF6 increases proliferation, and how beta cells permit ATF6-driven replication in high glucose (HG: 15 mM) but not normal glucose (NG: 7.5 mM).
Methods: To acutely induce ATF6 activation, dispersed mouse and human islet cells were transduced with adenovirus expressing the N terminal domain of ATF6 fused to a destabilized DHFR; stabilizing DHFR with TMP activates ATF6. Beta cell proliferation was quantified by BrdU in insulin+ cells; mRNA or protein levels were estimated by qPCR or Western blot.
Results: ATF6 activation increased Cyclin E1 and Cyclin A2 but reduced Cyclin D2 levels. Surprisingly, ATF6 robustly induced E2F1 mRNA and protein in both NG and HG, even though ATF6 only increased proliferation in HG. E2F1 activity, measured by transcriptional targets Pola1, Mcm5, and Clspn, only increased in HG. pRb, a key inhibitor of E2F1, was phosphorylated (deactivated) only in HG, explaining low E2F1 activity in NG. Overexpressing active CDK4, which phosphorylates pRb, bypassed the requirement for HG and rescued ATF6-driven proliferation in NG in mouse beta cells. In human islet cells, overexpressing CDK6, but not CDK4, synergized with ATF6 activation to robustly increase beta cell proliferation.
Conclusion: Beta cells engage a safety mechanism to avoid inappropriate cell number increase by allowing stress-induced replication only during glucose excess. Here we establish E2F1 as a key ATF6 target driving proliferation and identify CDK4/6-pRb as a glucose sensor that permits ATF6-induced E2F1 to expand beta cell number only when more insulin is needed.

Disclosure
H.V. Landa Galvan: None. T. Castro: None. J.J. Noel: None. G. Avila Llamas: None. R.B. Sharma: None. L.C. Alonso: None.

Funding
National Institute of Diabetes and Digestive and Kidney Diseases (R01DK124906), (R01DK114686), (R01DK113300), and (R01DK135304)
1764-P: Cross Talk between Pancreatic Mesenchymal Stem Cells and Macrophages Facilitates ß-Cell Decompensation in Obesity
Authors: XU WEILONG , JIN LIANG , YU JIANGYI 
Published: June 2024

Introduction & Objective: Obesity has long been recognized as a significant risk factor for developing type 2 diabetes mellitus (T2DM), the mechanisms triggering β-cell compensation and subsequent decompensation are still not fully understood. Our research has brought to light that in conditions of decompensation, macrophage presence in pancreatic islets is significantly increased while the population of mesenchymal stem cells (MSCs) concurrently decreases, which may reveal the true cause of dynamic change of pancreatic islets.
Methods: Single-cell sequencing methods can comprehensively characterize the diversity of cell types. In this study, we utilized a murine model of T2DM, established by feeding wild-type C57BL/6J mice with a high-fat diet (HFD), combining single-cell sequencing technology to investigate the effects and molecular mechanisms of cell interaction on β-cell decompensation.
Results: Our results show that pancreatic islet macrophages cause TNF-α dependent inhibition of Wnts release in MSCs, which leads to a decrease in β-cell numbers and insulin secretion. We also demonstrated that the loss of macrophages somewhat alleviates obesity-induced insulin resistance, while the injection of fresh MSCs can completely reverse β-cell decompensation. Meanwhile protective measures against HFD-induced β-cell dysfunction in mice were observed following the selective removal of macrophages and the subsequent introduction of MSCs.
Conclusion: These findings underscore the pivotal role of communication between macrophages and MSCs in modulating β-cell adaptive responses and functional impairment in obesity. Elucidating a precise mechanism for the effect of obesity on interaction between macrophages and MSCs will broaden our understanding of the pathophysiological development of diabetes and facilitate the design of better tools for diabetes prevention and treatment.

Disclosure
W. Xu: None. L. Jin: None. J. Yu: None.

Funding
National Natural Science Foundation of China (82205025,82174293,82104751); Forth Batch of Construction Program for Inheritance Office of Jiangsu Province Famous TCM Experts (No.[2021]7).
1771-P: Comprehensive Characterization of Individual Extracellular Vesicles from Beta-Cell Model Systems
Authors: ABUELREICH SARAH , LIMA CARINNA , ESPARZA DIANA , GHAELI IMA , THURMOND DEBBIE C. , JOVANOVIC-TALISMAN TIJANA 
Published: June 2024

In the United States, type II diabetes is prevalent in approximately 34-36 million Americans. To improve patient outcomes, extracellular vesicles (EVs) have emerged as an exciting potential modality. EVs are nano-scale particles released from all types of cells; they contain metabolites, nucleic acids, proteins, and lipids. EVs are an exciting source of biomarkers, a promising avenue for therapeutics, and important in understanding intercellular communication. Due to the heterogeneity of EVs from complex biofluids and the low abundance of EVs from specific organs (e.g., beta cells) it is technically challenging to isolate and characterize EVs from specific cell types. Towards this, we developed a new tool to molecularly characterize individual, low-abundant EVs. We used our Single Extracellular Vesicle Nanoscopy (SEVEN) approach, which combines affinity isolation and super-resolution microscopy, to characterize EVs from beta cell model systems. In particular, we characterized EVs from INS-1 832/13 beta cells, EndoC-beta H1 cells, and nondiabetic cadaveric human islets cultured ex vivo from two donors; EVs from L6.GLUT4myc myotube cells served as controls. The average diameter of beta cell EV ranged from 84 nm (islets) to 95 nm (INS-1 cells), while the average detected number of tetraspanins CD9, CD63, and CD81 ranged from 12 (INS-1 cells) to 17 (islets); as expected, all EVs displayed large heterogeneities in size, content, and circularity. In summary, we molecularly characterized individual EVs from cultured beta cell model systems and deciphered unique multiparametric information about their properties. This work paves the road to understanding the unique properties of EVs from beta cells. Ultimately, we hope to exploit these tools to better understand the role of EVs in normal and diabetogenic conditions.

Disclosure
S. Abuelreich: None. C. Lima: None. D. Esparza: None. I. Ghaeli: None. D.C. Thurmond: Consultant; Truebindings. T. Jovanovic-Talisman: None.

Funding
Dorrance Family Research FundWanek Family and City of HopeCUBRINIDDK 1T32DK131943
1780-LB: Establishing a Mouse Model Resembling UTI Development in the Context of Type 2 Diabetes
Authors: SANCHEZ-ZAMORA YURIKO I. , LOPEZ-TORRES JEIMY M. , LI ROLLIN , OLIVERIO ALEXANDRIA , COTZOMI-ORTEGA ISRAEL , SANCHEZ-ORELLANA GAMALIEL , DE DIOS RUIZ-ROSADO JUAN 
Published: June 2024

Introduction and Objective: Urinary tract infections (UTIs) are more severe in patients with type 2 diabetes mellitus (T2DM) due to various factors such as glycosuria and impaired immune responses. However, the precise mechanisms by which uropathogens exploit these conditions to colonize the urinary tract remain inadequately understood, partly due to the absence of suitable animal models. This study aims to establish a mouse model that mimics UTI development in individuals with diet-induced T2DM (UTI-T2DM model).
Methods: Diet-induced obese (DIO) male mice were fed special diets for 12, 16, and 20 weeks-high-fat diet (HFD, 60% fat) or low-fat diet (LFD, 10% fat). Subsequently, HFD and LFD mice were infected with uropathogenic E. coli (UPEC, 1x108 CFUs) via transurethral inoculation. Diabetes-like criteria were assessed through body weight, glucose levels, insulin levels, and oral glucose tolerance tests (OGTT). Bacterial burden was measured at 24- and 48-hours post-infection in collected bladders, prostates, ureters, and kidneys. The antimicrobial capacity of neutrophils isolated from infected HFD and LFD mice was evaluated. Differences between groups were analyzed using the t-test and Mann-Whitney U test, p-value is ≤0.05.
Results: DIO-HFD mice present higher body weight, hyperglycemia and hyperinsulinemia at 12, 16 and 20 w.s.d. compared to LFD mice. DIO-HFD mice exhibited significantly more bacterial burden in the urinary tract compared to LFD mice at 20 w.s.d. The bactericidal capacity of neutrophils from DIO-HFD mice was significantly impaired compared to their LFD counterparts.
Conclusions: DIO-HFD mice exhibit features resembling human T2DM and are significantly more susceptible to UTIs, making them a valuable model for investigating UTI susceptibility in the setting of diabetes.

Disclosure
Y.I. Sanchez-Zamora: None. J.M. Lopez-Torres: None. R. Li: None. A. Oliverio: None. I. Cotzomi-Ortega: None. G. Sanchez-Orellana: None. J. Ruiz-Rosado: None.

Funding
Research Institute at Nationwide Children's Hospital (AWD0000TBD), K01 NIH (DK128379).
1797-LB: Detection of Potential Therapeutic Target Associated with Coronary Artery Disease in Type 2 Diabetes Patients—System Biology Approach
Authors: MALIK ZUBBAIR , DASHTI MOHAMMED H. , JOHN SUMI E. , NIZAM RASHEEBA , AL-MULLA FAHD , THANGAVEL ALPHONSE T. 
Published: June 2024

Introduction & Objective: Type 2 diabetes (T2D) and coronary artery disease (CAD), co-morbidity of which presents mortality risk, are both systemic diseases linked with altered immune response. Treatments for the co-morbid condition of T2D and CAD are not yet developed to a satisfactory level, because of lack in the understanding the linkage between them. We aim to investigate the genes that are co-expressed in T2D and CAD in order to gain a better understanding of the common causal relationship between these diseases, and to identify potential biomarkers and targets for the treatment of T2D and CAD.
Methods: We identified differentially expressed genes (DEGs) that are co-expressed in T2D and CAD genes from CAD and T2DM patients. We performed pathways analysis to predict the commonalities between the signaling pathways and molecular networks attributed to these two diseases.
Results: We identified 451 DEGs in T2D and 644 DEGs in CAD patients compared with healthy controls. Of these DEGs, 32 were shared between the two comparisons. These common DEGs significantly mapped to shared pathways. Such shared pathways can be considered as partly accounting the associations between these two disorders. Of the common DEGs, TLR4, IGF1, UBB, MAPK1, CCND1, MYC, JUN and MMP9 are key genes of the molecular network with acceptable diagnostic power in T2DM and CAD datasets. We further predicted the miRNAs and transcription factors for these key genes.
Conclusion: Our study identified key genes that might play critical roles in both T2D and CAD. These findings may lead new understanding of the associations between CAD and T2D and facilitate novel treatment or prevention strategies. However, further experimental validations and clinical trials need to be pursued to verify our results.

Disclosure
Z. Malik: None. R. Nizam: None. F. Al-Mulla: None. A.T. Thangavel: None.
18-PUB: The Efficacy and Safety of Oral Antidiabetic Drugs Added to Short-Term CSII in Patients with Type 2 Diabetes
Authors: JIANG WEI , CHEN DANRUI , XU WEN , ZENG LONGYI 
Published: June 2024

Objective: Short-term continuous subcutaneous insulin infusion (CSII) has been proved to be efficacy in T2D patients. However, limited evidence is available about the effect of oral anti-diabetic drugs (OADs) added to short-term CSII in T2D. This study is aimed to compare the efficacy of OADs added to CSII with CSII alone on glucose control and glycemic variability (GV) in T2D.
Methods: A total of 206 hospitalized T2D patients who received CSII alone (CSII group, n=78) or CSII plus OADs (+OADs group, n=128) were included. The patient’s glycemic control and GV indices were derived from capillary blood glucose (BG) monitoring seven times a day. The insulin doses and time to achieve target BG (FBG&lt;7mmolL and 2h postprandial BG&lt;10mmol/L) were recorded.
Results: These patients were 52.5±13.0 years old, with diabetes duration of 5.8±5.9 years, and HbA1c of 9.45±2.15%. Compared with those in the CSII group, FBG (-1.39±2.40 mmol/L vs. -0.31±2.05 mmol/L), 2hBG after breakfast (-2.68±5.06 mmol/L vs. -1.16±4.26 mmol/L), 2hBG after lunch (-5.09±5.01 mmol/L vs. -2.76±5.08 mmol/L), 2hBG after supper (-3.32±4.69 mmol/L vs. -1.60±4.58 mmol/L), BG before lunch (-3.63±4.93 mmol/L vs. -2.09±3.37 mmol/L), BG before bedtime (-2.65±4.28 mmol/L vs. -1.38±4.11 mmol/L) after therapy in + OADs group decreased more obviously (all p&lt;0.05). Moreover, +OADs group exhibited lower GV indices (SDBG: 1.89±0.55 mmol/L vs. 2.21±0.79 mmol/L; PPGE: 2.41±0.97 mmol/L vs. 2.79±1.09 mmol/L; LAGE: 5.32±1.62 mmol/L vs. 5.96±1.93 mmol/L; MAGE: 4.14±1.70 mmol/L vs. 5.08±2.81 mmol/L; and CV: 0.24±0.08 vs. 0.27±0.09, respectively) compared to CSII group (all p&lt;0.05). Incidence of hypoglycemia was lower in +OADs group (21.1% VS 37.6%, p&lt;0.05). The insulin doses and time to achieve target BG did not differ between the two groups.
Conclusions: OADs added to short-term CSII could further improve glycemic control and GV indices with lower incidence of hypoglycemia in T2D patients compared with CSII alone.

Disclosure
W. Jiang: None. D. Chen: None. W. Xu: None. L. Zeng: None.