bluuebunny/crossref_metadata_2025_split huggingface dataset:
1723-P: ATF6α Is Required for Pancreatic Beta-Cell Proliferation during Acute Severe Insulin Resistance
Authors: DARKO CHRISTINE O. , WANG YING , CASTRO THALIA A. , ALONSO LAURA C. 
Published: June 2024

Introduction: Developing tools to expand beta cell mass is a critical goal towards a true solution to insulin-dependent diabetes. Sub-threshold activation of the UPR increases beta cell proliferation in hyperglycemic conditions via the Activating Transcription Factor 6 (ATF6) arm of UPR. ATF6α overexpression is sufficient to increase beta cell proliferation in high glucose in ex vivo islet cell cultures, and knockdown of ATF6α reduces glucose-induced proliferation. However, chronic beta cell deletion of ATF6α has been reported to cause minimal disruption to healthy biology. It is unknown if ATF6α participates in stress-induced beta cell proliferation in vivo.
Methods: Healthy C57BL/6N, or conditional beta cell ATF6α deletion (with Ins1cre: +/+Cre+, F/+Cre+ or F/FCre+ genotypes studied) male and female mice aged 10-15 weeks were implanted with Alzet minipumps containing 10nmol of S961 (insulin receptor antagonist) or vehicle for 7 days. Metabolic testing was performed, and pancreatic islets were isolated for qPCR analysis.
Results: Under unstressed conditions, beta cell ATF6α deletion did not alter systemic glucose metabolism. Healthy C57BL/6N mice treated with S961 developed marked hyperinsulinemia, hyperglycemia, and glucose intolerance. RNA from pancreatic islets isolated after 7 days of S961 showed molecular evidence of ER stress and increased proliferation markers; male and female mice were similar. Beta cell ATF6α deletion did not impact circulating metabolic parameters during severe insulin resistance, or surprisingly, the islet response to insulin resistance stress. However, the induction of proliferation markers in islets by S961 was significantly impaired in ATF6α deleted mice.
Conclusion: Chronic deletion of ATF6α in beta cells from development through adulthood does not impair beta cell homeostasis under unstressed conditions, but beta cell ATF6α is required for the proliferation response to acute severe insulin resistance in live mice.

Disclosure
C.O. Darko: None. Y. Wang: None. T.A. Castro: None. L.C. Alonso: None.

Funding
National Institutes of Health (R01DK135304, R01DK124906, and R01DK114686)
1728-P: The Nkx6.1 Binding Partner Mef2D Modulates Beta-Cell Insulin Secretion and Cell Survival
Authors: TESSEM JEFFERY S. , CRABTREE JACKIE 
Published: June 2024

We have explored Nkx6.1 binding partners and have shown that the transcription factor Mef2D is expressed in the beta cell and interacts with Nkx6.1. Interestingly, Mef2D mRNA and protein levels decrease as a function of aging in primary rat islets (77±27.3% reduction in mRNA and 62±13.4% reduction in protein). We sought to understand how changes in Mef2D levels impinge on beta cell insulin secretion, and survival. We observed that Mef2D overexpression impaired mitochondrial respiration at complex I (41±9.6% decrease), complex II (53±6.4% decrease), complex V (43±5.2% decrease), complex II linked oxidative phosphorylation (47±3.1% decrease) and maximal respiration (41±6.1% decrease), while Mef2D knockdown increased complex II linked oxidative phosphorylation (42±11.4%, increase) and maximal respiration (34±13.0%, increase). Mef2D overexpression decreased glucose stimulated insulin secretion (43±4% decreases) and cell survival with etoposide, camptothecin, and thapsigargin treatment (32±4.1%, 38±6.2%, and 16±4.8% decreases, respectfully). Conversely, Mef2D knockdown increased glucose stimulated insulin secretion (75±7% increase) and cell survival with etoposide, and thapsigargin treatment (25±3.7% and 168±11.4% increases, respectfully). The observed changes in respiration, insulin secretion, and cell survival corresponded with modulated electron transport chain component expression, including expression of complex I component mtND6, with Mef2D overexpression decreasing mtND6 mRNA (49±9.7% decrease) and protein (a 37±6.6% decrease). Our findings define Mef2D as a critical factor for modulating insulin secretion and beta cell survival through modulation of beta cell mitochondrial function.

Disclosure
J.S. Tessem: None. J. Crabtree: None.

Funding
National Institutes of Health (R15DK124835)
173-OR: A Clinical Study of Novel Antimicrobial Peptide PL-5 Topical Spray for Mild to Moderate Infectious Wounds of Diabetic Foot
Authors: QIAN LI , WANG AIPING , HU WEN , WANG GUOFENG , SUN XINJUAN , LIU YU 
Published: June 2024

Background: Antimicrobial peptide PL-5 spray is a topical antimicrobial peptide drug with novel mechanism of action and may improve the cure efficiency of diabetic foot infections. We studied the clinical efficacy and safety of investigational PL-5 spray in the treatment of mild to moderate diabetic foot ulcers in combined with standard debridement procedure.
Methods: A multicenter, randomized, double-blind, placebo-controlled clinical trial was conducted in four hospitals in China. Qualified subjects with mild to moderate diabetic foot ulcers were randomly assigned (2:1 ratio) into PL-5 and placebo groups plus a standard debridement. The primary endpoint of the study was the clinical efficacy at day 1 after the end of treatment (EOT1); the secondary endpoints included the clinical efficacy of treatment at day 7 after EOT(EOT7), microbiological efficacy, drug-resistant bacteria clearance rate, wound healing rate, and safety outcomes evaluated at EOT1 and EOT7, respectively.
Results: Subjects in PL-5 and placebo groups (32 vs 15 cases) showed no statistical differences in demographic and clinical characteristics. The clinical efficacy (cure/improvement ratio) in PL-5 group at EOT1 was higher than that in control group (1.33 vs 0.55, p=0.0764). Among the secondary endpoints, the clinical efficacy at EOT7 in PL-5 and control groups were 1.6 vs 0.86, the microbial eradication rates were 57.89% vs 33.33% (EOT1) and 64.71% vs 40.00% (EOT7); the drug-resistant bacteria clearance rates were 71.43% vs 50% (EOT1), respectively. The safety parameters showed no difference between two groups (24.24% vs 33.33%).
Conclusion: With limited samples, antimicrobial peptide PL-5 spray still shows strong potentials on efficacy and safety against the wound infections caused by drug-resistant bacteria. It can be anticipated that topical PL-5 treatment significantly improved the recovery speed of the diabetic foot wounds in further amplified study.

Disclosure
L. Qian: None. A. Wang: None. W. Hu: None. G. Wang: None. X. Sun: None. Y. Liu: None.
1735-P: AKT Modulates Glucose Sensing and Glucagon Secretion in Alpha Cells
Authors: NEVES AMANDA F. , LUBACZEUSKI CAMILA , BOZADJIEVA KRAMER NADEJDA , ANDRADE LOUZADA NETO RUY , BERNAL-MIZRACHI ERNESTO 
Published: June 2024

In both T1DM and T2DM, glucagon secretion is impaired and no longer inhibited by hyperglycemia nor insulin, suggesting a defect in the insulin signaling via IRS/PI3k/Akt on pancreatic α-cells. Using a mouse model with constitutive activation of Akt in α-cells (αpCall), we investigated the impact of insulin signaling activation on glucagon secretion at different glucose concentrations. The αpCall mice exhibited lower body weight and hypoglycemia in early life. Given the mosaic expression of the transgene in α-cells, αpCall mice displayed normal glucose homeostasis, glucagon, and insulin secretion. In isolated islets, α-cells from αpCall mice showed increased expression of glucagon and the activation of mTORC1 signaling. In addition, α-cells from αpCall mice exhibited increased exocytosis and glucagon secretion stimulated by low glucose. This result was accompanied by elevated expression levels of Na+ and Ca2+ channels, along with an increase in Na+ and Ca2+ currents. Conversely, exposure of Akt-expressing α-cells to escalating glucose concentrations demonstrated a better suppression of glucagon secretion at high glucose levels. Throughout these experiments, insulin expression and secretion remained consistent under all glucose-stimulated conditions. In summary, our findings highlight the crucial role of AKT signaling activation in α-cells: it suppresses glucagon secretion in hyperglycemic conditions while enhancing glucagon secretion in low-glucose environments. This suggests that insulin signaling through the Akt pathway regulates α-cell sensitivity and glucagon secretion in response to glucose.

Disclosure
A.F. Neves: None. C. Lubaczeuski: Employee; Fractyl Health, Inc. N. Bozadjieva Kramer: None. R. Andrade Louzada Neto: None. E. Bernal-Mizrachi: None.

Funding
National Institutes of Health (5I01BX002728-08)
174-OR: Genetic Variation in GLP-1R Modify the Risk of Hypoglycemia in Response to Intensive Glycemic Control in Adults with Type 2 Diabetes
Authors: XUE QIAOCHU , LI PIAOPIAO , JAGANNATHAN RAM , PASQUEL FRANCISCO J. , UMPIERREZ GUILLERMO , PHILLIPS LAWRENCE S. , ALI MOHAMMED K. , SHAO HUI 
Published: June 2024

Introduction: Hypoglycemia is a potential side effect of Intensive Glycemic Control (IGC) in diabetes management. We aimed to investigate whether individuals with certain GLP1R gene variations were at greater hypoglycemia risk with IGC.
Methods: A dynamic cohort design with time-varying exposures was employed using electronic health records linked to survey data from 8,848 individuals in the All-of-Us database. Subjects with type 2 diabetes and antidiabetic medication use could transition between the IGC exposure group (A1c &lt; 7.0%) and the moderate glycemic control group (A1c 7%-8.5%) during follow-up or were censored at their last visit, death, end of the study, or if A1c exceeded 8.5%. Per-protocol analysis was conducted using mixed-effects Cox proportional regression models, adjusting for demographics and a comprehensive set of time-varying variables, including disease histories, lab values, medications, and patient-reported conditions.
Results: During a median follow-up period of 6.2 years, we documented 841 incident cases of hypoglycemia (incidence rate:1.34 per 100 person-years). Compared to the moderate GC group, the IGC group had a higher hypoglycemia risk (hazard ratio (HR): 1.06, 95% CI:1.00-1.12). Thirteen out of 15 GLP1R genetic variants significantly modified such risk, demonstrating a notable variation in risk across different genotypes, with HR ranging from 0.46 to 1.19. Combining these variants in a polygenic risk score showed that higher scores were associated with higher IGC-associated hypoglycemia risk (high score: HR 1.27, 95% CI [1.13-1.43] vs Low score: HR 0.57, 95% CI [0.43, 0.77). Sensitivity analyses excluding all GLP-1RA users yielded consistent results.
Conclusion: Our findings indicate that GLP1R variants play a modulating role in IGC-associated hypoglycemia risk, independent of GLP-1RA use. This effect suggests the prominent role of GLP1R genes in safe glucose-lowering among patients with type 2 diabetes.

Disclosure
Q. Xue: None. P. Li: None. R. Jagannathan: None. F.J. Pasquel: Research Support; Tandem Diabetes Care, Inc., Insulet Corporation, Dexcom, Inc., Ideal Medical Technologies, Novo Nordisk. Consultant; Dexcom, Inc., Medscape. G. Umpierrez: Research Support; Abbott, Bayer Inc., Dexcom, Inc., AstraZeneca. Advisory Panel; Dexcom, Inc. L.S. Phillips: Other Relationship; Diasyst, Inc. Research Support; Kowa Pharmaceuticals America, Inc., Janssen Pharmaceuticals, Inc., AbbVie Inc., Novo Nordisk, GlaxoSmithKline plc, Abbott, Sanofi-Aventis U.S., Pfizer Inc. M.K. Ali: Advisory Panel; Eli Lilly and Company. H. Shao: Consultant; Eli Lilly and Company.
1747-P: Glucolipotoxicity Inhibits Proinsulin Processing through Disrupting V-ATPase Function Leading to Impaired Acidification within Secretory Granules
Authors: IIDA HITOSHI , TAKIGUCHI MAMI , NISHIDA YUYA , WATADA HIROTAKA 
Published: June 2024

Increase in serum proinsulin level reflects dysfunction of pancreatic beta cells. Insulin is secreted by pancreatic beta cells after the precursor proinsulin is processed by prohormone convertase (PC) 1/3 in secretory granules (SGs). In the progression of diabetes where pancreatic beta cells are under excess fatty acids and high glucose, insulin biosynthesis is impaired and proinsulin is secreted as an unprocessed form of insulin. However, the exact mechanism of the impairment of proinsulin processing is unclear. As a first step to elucidate its mechanism, we used islets isolated from db/db mice and islets treated with high glucose and palmitate (HGPal), as a model of glucolipotoxicity. As PC1/3 enzyme function is known to be dependent on the luminal acidity in the SGs, we investigated the pH in both islets and found decrease in the acidity of the entire cells by labeling cells with fluorogenic pH indicator with flow cytometry. We also detected decrease in the protein level of insulin and change in the protein expression pattern of PC1/3 by immunoblotting. Morphological analysis with electron microscope revealed that accumulation of immature SGs in these islets probably due to the accumulation of proinsulin inside. Given that the V-ATPase plays an essential role to maintain the acidity of SGs as a proton pump, both fractionation assay and proximity ligation assay revealed that HGPal stimuli inhibit the assembly formation of two major domain V1 and V0 in of V-ATPase Our results demonstrate that glucolipotoxicity altered the luminal acidity in SGs and impaired the proinsulin processing through disrupting V-ATPase function. We anticipate these results may explain underlying molecular mechanisms of the increase in the serum proinsulin level reflecting dysfunction of pancreatic beta cells.

Disclosure
H. Iida: Research Support; Sumitomo Dainippon Pharma Co., Ltd. M. Takiguchi: Research Support; Sumitomo Dainippon Pharma Co., Ltd. Y. Nishida: Research Support; Sumitomo Dainippon Pharma Co., Ltd. H. Watada: Speaker's Bureau; Bayer Inc., Sanofi, Novo Nordisk, Sumitomo Dainippon Pharma Co., Ltd., Abbott Japan Co., Ltd., Eli Lilly and Company, Boehringer-Ingelheim, Daiichi Sankyo, Taiho Pharmaceutical Co. Ltd., Kowa Company, Ltd., Teijin Pharma Limited, Mitsubishi Tanabe Pharma Corporation. Research Support; Sumitomo Dainippon Pharma Co., Ltd., Boehringer-Ingelheim, Mitsubishi Tanabe Pharma Corporation, LifeScan Diabetes Institute, Abbott Japan Co., Ltd., Teijin Pharma Limited, Takeda Pharmaceutical Company Limited, Taiho Pharmaceutical Co. Ltd., Sanwa Kagaku, Souiken.

Funding
JSPS KAKENHI (JP 20K17501)
1754-P: Investigating the Interplay between T-Cell Infiltration, ROS Detoxification, and Pancreatic Beta-cell Dysfunction in Type 1 Diabetes Pathogenesis
Authors: LAZIMI CHARLES , MATHEWS CLAYTON E. , PHELPS EDWARD 
Published: June 2024

Introduction & Objective: Reactive oxygen species (ROS), byproducts of cellular metabolism, are implicated in T1D progression, causing lipid, protein, and DNA damage, along with impaired β-cell function and apoptosis. Notably, at the onset of T1D, β-cells exhibit dysregulated glucose metabolism, resulting from decreased glucose uptake and impaired utilization. This metabolic perturbation diminishes NADPH production, a critical antioxidant cofactor from glycolysis and the pentose phosphate pathway (PPP). Consequently, islets in T1D individuals may exhibit compromised ROS-neutralizing abilities, heightening susceptibility to oxidative damage. The objective of this study is to determine glucose metabolism's role in β-cell antioxidant defense and T1D-related dysfunction. We hypothesize that insulitic islets in T1D are more vulnerable to damage from ROS compared to islets in individuals without diabetes and that diminished ROS detoxification contributes significantly to β-cell loss and dysfunction in T1D.
Methods: Islets in live pancreatic tissue slices from both nondiabetic and recent-onset diabetic donors were acutely challenged with hydrogen peroxide (H2O2), and palmitate, followed by glucose stimulations. Real-time monitoring of ROS levels, utilizing ROS biosensor GRX1-roGFP2 and chemical ROS indicators, were conducted.
Results & Conclusion: While it is generally the case that chronic hyperglycemia induces oxidative β-cell damage, our observations suggest that acute glucose stimulation reduces baseline ROS levels by promoting increased GSH in healthy β-cells. Following various ROS challenges including, high glucose stimulations quickly reverted their oxidative effects in healthy β-cells. These results support the concept that poor beta cell glucose responsiveness in T1D increases β-cell susceptibility to ROS.

Disclosure
C. Lazimi: None. C.E. Mathews: None. E. Phelps: Research Support; Immunocore, Ltd, MESO SCALE DIAGNOSTICS, LLC.
1755-P: The Development of Antagonists Targeting Olfr109 to Treat Diabetes
Authors: GE XIAOYAN , CHENG JIE , YANG ZHAO , YU XIAO , SUN JINPENG 
Published: June 2024

The olfactory receptor Olfr109 is activated in diabetic models and then impairs islet β cell functions. Antagonizing Olfr109 is a new potential therapeutic strategy to treat diabetes. Previous studies showed that pepducin o109-i2-2 targeting Olfr109 improved islet function and glucose homeostasis. To further obtain the higher potency antagonists, we rationally designed the peptide antagonists targeting Olfr109. We successfully convert the peptide agonist insB 9:23 to the antagonist Ssc-S(R) by combining mutations and non-natural amino acid substitution at specific positions. Importantly, the combined antagonist of Ssc-S(R) had a more significant effect on the improvement of glucose metabolism in diabetic mice. In response to Ssc-S(R), the decreased insulin secretion and increased endoplasmic reticulum stress were significantly alleviated. Therapeutic administration of Ssc-S(R) could significantly ameliorate intra-islet inflammatory responses and improved glucose homeostasis in both Akita and HFD-fed mice. Notably, no significant differences were observed in ins2 WT/Akita Olfr109-/- mice and HFD-fed Olfr109-/- mice. Taken together, we have developed the Olfr109-specific antagonist Ssc-S(R), which may provide new clues for the treatment of islet inflammation and diabetes.

Disclosure
X. Ge: None. J. Cheng: None. Z. Yang: None. X. Yu: None. J. Sun: None.
1767-P: A Modifying Effect of Genetic Background on S64F MAFA-Induced Dysglycemia
Authors: LOYD ZACHARY , LEE DONGSOO , GUO MIN , STEIN ROLAND , CHA JEEYEON 
Published: June 2024

Introduction & Objective: The MAFA transcription factor is an essential regulator of mature pancreatic islet β cell function. A rare missense variant of human MAFA, Ser64Phe (S64F), was identified as a MODY gene in patients with familial insulinomatosis or diabetes mellitus (1). S64F MAFA carriers either became hypoglycemic due to multifocal pancreatic insulinomas (insulinomatosis) or develop diabetes, with men more likely to become diabetic and women develop insulinomatosis. A mouse model harboring this mutation recapitulated these sex-dependent glycemic phenotypes (2). Here we sought to investigate the impact of mouse genetic background on S64F MAFA-induced dysglycemia.
Methods: S64F MAFA mutant mice were bred either on a mixed C57/Bl6J (C57) and SJL background, or C57 alone. Glucose tolerance testing assessed serum glucose at t=0 (fasting), 15, 30, 60, and 90 minutes post intraperitoneal injection (0.2mg/kg dextrose). Statistical analysis was performed by Two-way ANOVA. Glucose-stimulated insulin secretion was also assessed at 0, 15 and 30 minute time points. Cut&Run determined DNA-protein interactions to help identify binding targets of MAFA in MIN6 β cells.
Results: Mixed background S64F MAFA male mice were diabetic while females showed improved tolerance compared to WT siblings. In the C57 background, males were euglycemic while females showed improved glycemia. Insulin secretion was impaired only in mixed background mutant males. Cut&Run analysis performed for endogenous MAFA in MIN6 cells identified enrichment at known MAFA targets such as Ins1, Ins2, and Slc2a2, among others, thus verifying our test system.
Conclusion: Genetic background influenced S64F MAFA-dependent glycemia in a sex-dependent manner. Ongoing studies investigate differential targets of this mutant MAFA compared to those of the wild-type protein by Cut&Run analysis within each sex and validate differential targets by RNAScope.

Disclosure
Z. Loyd: None. D. Lee: None. M. Guo: None. R. Stein: None. J. Cha: None.

Funding
National Institutes of Health (5K08DK132507), Burroughs Wellcome Fund Career Award for Medical Scientists
1768-P: The Impact of IL-1 in Islet Antiviral Responses
Authors: BARTOSIAK JACOB , CORBETT JOHN A. 
Published: June 2024

Introduction & Objective: Viruses, particularly members of the picornavirus family, are correlated with the onset of T1D. For this reason, viral infection has been identified as an environmental trigger for T1D onset, specifically due to its ability to stimulate the production and release of pro-inflammatory cytokines into the islet. The purpose of this study is to define physiological functions of cytokine signaling in β-cells that may contribute to reduced virus-mediated damage and destruction of β-cells.
Methods: C57BL/6J and DBA/2J mice were infected with encephalomyocarditis virus (EMCV), a highly inflammatory picornavirus that causes dysglycemia in genetically susceptible mouse strains. Pancreas and serum were collected from the animals throughout the course of infection. Insulitis and β-cell morphology were evaluated by H&E and immunofluorescence and serum cytokine concentrations were analyzed by LEGENDplex anti-virus response assay. Furthermore, isolated mouse islets were treated with cytokines and gene responses and EMCV viral replication were measured by qRT-PCR.
Results: We show that C57BL/6J mice are resistant to EMCV infection and maintain islet architecture and glycemic control, despite immune cell infiltration. In contrast, EMCV infection of genetically susceptible DBA/2J mice results in destruction of β-cells, deterioration of islet morphology, and loss of glycemic control. Transiently elevated serum cytokines in C57BL/6J mice suggest successful restriction of EMCV replication whereas sustained elevation of these cytokines in DBA/2J mice suggests a failure of these mice to mount an effective antiviral response. Additionally, islets treated with IL-1β ex-vivo upregulate several antiviral genes and treatment of isolated islets with IL-1β prior to infection attenuates EMCV mRNA accumulation.
Conclusion: These studies suggest IL-1β signaling in β-cells during viral infection functions to activate protective antiviral defense mechanisms designed to limit β-cell damage.

Disclosure
J. Bartosiak: None. J.A. Corbett: None.

Funding
AI2212769