bluuebunny/crossref_metadata_2025_split huggingface dataset:
1592-P: Evaluating TRIB1 as a Genetic Driver of Fatty Liver Disease in an In Vitro Model of Carbohydrate-Mediated Lipid Accumulation
Authors: DEHGHANI TIMA , SHEWADE LEENA , GUO KARL , LLOYD DAVE , SATAPATI SANTHOSH 
Published: June 2024

Metabolic dysfunction associated steatotic liver disease (MASLD) is the most common liver disease and is characterized by increased lipid accumulation in the liver. Though the exact cause of manifestation is largely unknown, insulin resistance, type 2 diabetes and obesity are strongly associated with development and progression of MASLD. Recent literature emphasizes the role of genetics in the pathogenesis of MASLD. In several genome wide association studies, polymorphisms in Tribbles 1 (TRIB1) are significantly associated with MASLD. However, molecular mechanisms underlying TRIB1 and increased hepatic lipid accumulation are poorly understood. In this study we hypothesized that TRIB1 controls hepatic lipid homeostasis by regulating C/EBPα expression which is a known regulator of de novo lipogenesis (DNL). To understand the mechanism of action, we generated TRIB1, CEBPA, and RFWD2 gene knockouts in HepG2 cell line and in primary human hepatocytes and overexpression of TRIB1 in HepG2s. Knockout and overexpression cell lines were challenged for 24-72h with a cocktail of glucose, fructose, and insulin to mimic DNL conditions and evaluated lipid accumulation via confocal microscopy and gene expression analysis to understand mechanism of action. Lack of TRIB1 in primary human hepatocytes significantly increased lipid content compared to control cells under DNL conditions. Knockout of CEBPA and RFWD2 in HepG2’s significantly reduced lipid accumulation compared to controls. Overexpression of TRIB1 led to reductions in CEBPA gene expression and DNL; however, as TRIB1 overexpression waned, so did these attenuations. These data suggest that, while TRIB1 may regulate CEBPA expression, high expression levels are required to lessen the disease phenotype in this cell system. Strong TRIB1 inducers, or alternative regulators of CEBPA, may be required to leverage this mechanism in future therapeutics.

Disclosure
T. Dehghani: Employee; insitro. L. Shewade: Employee; insitro. K. Guo: Employee; insitro. D. Lloyd: Employee; insitro. S. Satapati: None.
1599-P: Understanding the Paradoxical Rise in Blood Glucose in the Context of a Low-Carbohydrate Diet
Authors: DERU LANDON , BAILEY BRUCE W. , BIKMAN BENJAMIN 
Published: June 2024

Introduction and Objective: Conventional medicine places markers of glycemic control as a key diagnostic and therapeutic target for metabolic disorders. Long-term adherence to a low-carbohydrate diet may improve glycemic control but may also cause a unique hormonal response to macronutrients that keeps blood glucose elevated. The purpose of this study was to identify an endocrine pattern explaining the phenomenon of elevated glucose on a subset of people that adhere to a carbohydrate-restricted diet.
Methods: Each participant (13 female, 11 male) completed three interventions which consisted of consuming an isovolumetric 300 kcal drink of either whey protein (PRO), dextrose (CHO), or olive oil (FAT) mixed in water. Blood was taken immediately prior to drink consumption and then every 30 minutes afterwards for 2 hours in each condition. Continuous glucose monitoring took place during each intervention.
Results: Glucagon was not different between FAT/CHO conditions (p = 0.28), but elevated in the PRO condition comparted to both FAT and CHO conditions (p &lt; 0.01). Insulin was not different between PRO/FAT (p = 0.22) or PRO/CHO (p = 0.30), but was higher in the CHO compared to the FAT condition (p &lt; 0.01). GLP-1 was not different between FAT/CHO conditions (p = 0.37), but was elevated in the PRO condition compared to the CHO and FAT conditions (p &lt; 0.01). GIP was different between all three conditions (p&lt;0.01). Glucose was not different between FAT/PRO conditions (p = 0.44), but was elevated in the CHO condition compared to the FAT and PRO conditions (p&lt;0.01).
Conclusion: The glucose load significantly raised plasma glucose, GIP, and insulin while decreasing glucagon, relative to the fat and protein loads. The protein load, in contrast, uniquely raised GLP-1 and glucagon relative to the other drinks. Adherence to a carbohydrate-restricted diet may result in an exaggerated glucagon response to PRO which may explain elevated glucose in this population.

Disclosure
L. Deru: None. B.W. Bailey: None. B. Bikman: None.

Funding
This work is supported by funds from Levels Health, Inc.
1620-P: Vagus Nerve Integrity Is Critical for GLP-1 (7-36) Safeness against Hypoglycemia
Authors: LOBATO CAROLINA B. , HOLST JENS J. 
Published: June 2024

Introduction & Objective: GLP-1 optimizes glycemic control mostly by stimulating insulin and suppressing glucagon secretion. During hypoglycemia, the glucagon suppressing activity is abolished through unclear pathways. The parasympathetic nervous system, via the vagus nerve, modulates the pancreatic hormone secretion during hypoglycemia. The vagus nerve fibers run along the esophagus and stomach walls, and innervate the pancreas distally. We investigated the role of the vagus nerve anatomical integrity in modulating pancreatic endocrine response to cholinergic activity and GLP-1 under hypoglycemia.
Methods: In situ, isolated rat pancreas (A); and pancreas and stomach (B) were perfused at severe hypoglycemia (glucose 1.5mM). Ach 1 µM, Ach 1 µM + GLP-1 (7-36) 1nM and GLP-1 (7-36) 1nM were sequentially infused (A: n = 6; B: n = 6). L-Arginine 10 mM was infused at the end of all experiments (positive control). Glucagon and SST levels were measured. Total hormone output was calculated. Statistical significance was settled at p&lt;0.05.
Results: During hypoglycemia, cholinergic stimulation suppresses SST and stimulates glucagon secretion. Active GLP-1 (7-36) overrides cholinergic activity by potentiating SST and suppressing glucagon secretion in the isolated pancreas (A), but GLP-1 (7-36) has no effect if the vagus nerve integrity is preserved (B). Once cholinergic stimulation is discontinued, GLP-1 (7-36) suppresses glucagon and stimulates SST secretion in both preparations.
Conclusion: Pancreatic cholinergic activity stimulates glucagon secretion during hypoglycemia through suppression of somatostatin secretion. Cholinergic signaling that is delivered through the gastric intramural autonomic ganglia and/or vagus nerve efferents to the pancreas is crucial for blunting GLP-1 (7-36) activity under hypoglycemia. These findings improve our understanding of GLP-1 physiology and shine light on the requirements to target vagal nerve function in optimizing pancreatic endocrine secretion.

Disclosure
C.B. Lobato: Research Support; Dexcom, Inc. J.J. Holst: Advisory Panel; Novo Nordisk A/S, Merck Sharp & Dohme Corp., Kallyope. Board Member; Antag Therapeutics.

Funding
Danish Diabetes Academy (NNF17SA0031406); "la Caixa" Foundation (LCF/BQ/EU21/11890081).
1639-P: Tirzepatide and Efruxifermin Demonstrate Therapeutic Benefits for NASH in a Preclinical Metabolic Syndrome Animal Model, B6-Alms1-del Mice
Authors: CHEN ZHONG , SHEN YANFEI , WANG HONGYAN , WANG HONGYU , LIANG JUAN , ZHAO JING , GAO XIANG , GAO MAOMAO 
Published: June 2024

The escalating prevalence of metabolic syndrome has led to NAFLD and its severe form, nonalcoholic steatohepatitis (NASH), becoming a major public health concern. While numerous anti-NAFLD/NASH agents have entered development pipelines, only Resmetirom has advanced to the NDA stage. There remains a high demand for novel therapies in the NAFLD/NASH field.We tested two promising anti-NASH agents, Tirzepatide and Efruxifermin in the B6-Alms1-del mice, which develop NASH spontaneously. B6-Alms1-del mice at 16 weeks of age received twice a week treatment of vehicle, 30 nmol/kg Tirzepatide or 30 nmol/kg Efruxifermin subcutaneously for 6 weeks. Our finding revealed that, compared with vehicle treatment, both Tirzepatide and Efruxifermin treatment significantly decreased body weight, plasma ALT and AST, fasting blood glucose and blood lipid. However, Efruxifermin demonstrated a significantly greater inhibitory effect on body weight than Tirzepatide treatment. Additionally, Tirzepatide significantly reduced the food intake of mice, while the effect of Efruxifermin on food intake was not significant. The results of metabolic parameters suggested that Efruxifermin's metabolic benefits on B6-Alms1-del mice did not mainly rely on reduced energy intake. Morphology analysis indicated that liver hypertrophy observed in B6-Alms1-del mice was marked reduced upon treatment with both Tirzepatide and Efruxifermin. Particularly, treatment with Efruxifermin nearly restored the liver weight of B6-Alms1-del mice to that of B6J mice. Consistently, Efruxifermin treatment exhibited more significant NASH resolution than Tirzepatide treatment.In summary, we demonstrated the therapeutic effects of Tirzepatide and Efruxifermin in B6-Alms1-del mice, which aligned with recent clinical observations. Consequently, B6-Alms1-del mice could serve as a valuable model for preclinical studies of anti-NASH agents targeting GLP-1R/GIPR and FGF21.

Disclosure
Z. Chen: None. Y. Shen: None. H. Wang: None. H. Wang: None. J. Liang: None. J. Zhao: None. X. Gao: None. M. Gao: None.
1685-P: Dapiglutide Is a Dual Agonist on Human GLP-1- and GLP-2-Receptors with a Biased and Prolonged Signaling Profile at the GLP-1R
Authors: GJELSTRUP LOUISE , KERSTIN LUNDHOLT BETINA , LARSEN BJARNE D. , JOHANSEN NICKLAS J. , OLSEN MINNA B. , MATHIESEN JESPER M. 
Published: June 2024

Dapiglutide, a potential first-in-class therapy targeting obesity and low-grade inflammation, is designed for activating both GLP-1 and GLP-2 receptors. In a MAD trial, healthy participants receiving once-weekly s.c. injections of dapiglutide up to 6 mg for 4 weeks showed dose-dependent body weight loss up to a mean 4.3%, and dose-dependent reductions of plasma glucose and insulin. At the cellular level, GLP-1R activation by native GLP-1 induces formation of its major second messenger cAMP and recruitment of β-arrestin. Recent studies hypothesized that biased agonists displaying lack of β-arrestin recruitment at the GLP-1R are beneficial in controlling blood glucose and body weight loss in DIO rats. Here we investigated the in vitro profile of dapiglutide, emphasizing on GLP-1R signaling bias and functional consequences.
Binding assays using 125-iodinated radioligands were used to estimate binding affinities of dapiglutide for human GLP-1R and GLP-2R. The human GLP-1R in vitro signaling profile was investigated in a kinetic cAMP formation assay and for recruitment of β-arrestin in HEK293 cells.
Initial in vitro characterization indicated that dapiglutide is more potent for binding to GLP-1R over GLP-2R, with estimated binding affinities of 38 nM and 102 nM, respectively.​ At the GLP-1R, dapiglutide showed signaling bias, displaying full agonist activity in cAMP formation, whilst having significantly blunted response to β-arrestin recruitment. Further in vitro characterization showed that dapiglutide-induced cAMP formation kinetics persisted for up to 12 hours unlike native GLP-1, potentially reflecting signal bias, lack of receptor desensitization, and a promising efficacy profile in the MAD trial.
Dapiglutide, a dual GLP-1/GLP-2 agonist, has a unique GLP-1R biased agonism signaling profile that combined with additional GLP-2R activity may translate into an efficacious weight management therapy in individuals with obesity.

Disclosure
L. Gjelstrup: Employee; Zealand Pharma A/S. B. Lundholt: Employee; Zealand Pharma A/S. B.D. Larsen: None. N.J. Johansen: Employee; Zealand Pharma A/S. M.B. Olsen: None. J.M. Mathiesen: Employee; Zealand Pharma A/S.
1710-P: Weight Stigma and Discrimination among Hispanics and Non-Hispanic Whites and Blacks with Obesity and Diabetes in the U.S.
Authors: GALINDO RODOLFO J. , ZABALA ZOHYRA , AREVALO GIULIANA , MOAZZAMI BOBAK , LECUBE ALBERT , RASHIED AMMAR A. , UMPIERREZ GUILLERMO 
Published: June 2024

Introduction: People with obesity experience stigma and discrimination for their physical appearance and weight. Data is limited among stigmatization and prejudices among Hispanics (HISP) and non-Hispanic Whites (NHW) and Blacks (NHB) with obesity and diabetes in the U.S. We compare prejudices, stigma and internal negative bias in these groups.
Methods: Observational study conducted at two academic centers, including adults &gt; 18ys, and BMI ≥30 kg/m2. We assessed prejudices with Anti-Fat Attitudes (AFA), stigmatizing experiences with Brief Stigmatizing Situations Inventory (SSI-B), and internalization of negative weight bias with Weight Bias Internalization Scale (WBIS) surveys.
Results: Among 233 participants (age 55.3±13 years, 62% females, BMI 37±6.4, 48% HISP, 10% NHW, 42% NHB), 73% and 22% had the perception of being individuals with overweight (OW) and obesity (OB), respectively. HISP had a higher AFA score (p&lt;0.001) compared to NHW and NHB. SSI-B score was similar across groups. NHW had a higher WBIS score compared to HISP and NHB (p=0.01).
Conclusions: Adults with obesity and diabetes in the U.S., HISP had higher aversion/prejudices towards people with obesity, NHW had higher internalization of negative bias, while stigmatizing experiences were not different across groups.
Table 1. Demographic Characteristics and Surveys Scores among Adults with Obesity and Diabetes

Disclosure
R.J. Galindo: Consultant; Abbott. Other Relationship; Dexcom, Inc. Consultant; Bayer Inc. Other Relationship; Novo Nordisk, Eli Lilly and Company. Consultant; Boehringer-Ingelheim, AstraZeneca. Z. Zabala: None. G. Arevalo: None. B. Moazzami: None. A. Lecube: None. A.A. Rashied: None. G. Umpierrez: Research Support; Abbott, Bayer Inc., Dexcom, Inc., AstraZeneca. Advisory Panel; Dexcom, Inc.

Funding
National Institutes of Health (P30DK111024 (RJG, GEU), and K23DK123384 (RJG) and R03DK138255 (RJG))
1729-P: Hypertonicity Mediates Glucose-Induced First-Phase Insulin Secretion
Authors: KAMAT VARUN , SWEET IAN 
Published: June 2024

Biphasic insulin secretion is an intrinsic characteristic of the pancreatic islet and has clinical relevance due to the loss of first phase in patients with Type 2 diabetes. As it has long been shown both in vitro and in vivo that first phase insulin secretion only occurs in response to rapid, but not gradual, changes in glucose, we tested the hypothesis that hypertonicity is driving first phase insulin secretion. The hypothesis was tested with perifusion analysis of rat. mouse and human islets by counterbalancing increases in D-glucose with decreases in L-glucose (a membrane impermeable form of glucose) so that insulin secretion rate (ISR) and other parameters associated with its regulation (NAD(P)H, calcium, cAMP production rate (cAMP PR)) could be measured in response to D-glucose in the absence of a change in tonicity. In response to a rapid rise in D-glucose, biphasic increases were observed for all 4 measured parameters. Remarkably, the appearance of the first phase component was wholly dependent on changes in tonicity: no first phase in NAD(P)H, cytosolic calcium, cAMP PR, or ISR was observed when increased D-glucose concentration was counterbalanced by decreases in either L-glucose (or another membrane-impermeable compound mannitol). Notably, rapid increases in L-glucose without any change in D-glucose resulted in first phase responses in all measured parameters that were kinetically similar to those observed in response to D-glucose. The effects of changes in osmolarity on calcium and ISR were blocked by a specific inhibitor of L-type calcium channels. Taken together, it appears that first phase insulin secretion is a result of a short-lived hypertonicity occurring during rapidly increasing glucose that enhances glucose metabolism, activation of L-type calcium channels and elevation of cAMP, that briefly augments the same mechanisms mediating second phase insulin secretion.

Disclosure
V. Kamat: None. I. Sweet: Employee; EnTox Sciences, Inc. Advisory Panel; Regenerative Medical Solutions.

Funding
National Institutes of Health (R01 GM148741); The Helmsley Foundation (#FA218303); National Institutes of Health IIDP Technology Resource Award (TRA2023)
1733-P: Foxo3 and Heterogeneity of Dedifferentiating ß-Cells
Authors: SON JINSOOK , ACCILI DOMENICO 
Published: June 2024

Type 2 diabetes is associated with β-cell dedifferentiation. This process is linked to a loss of Foxo1 function and can be recapitulated by genetic inactivation of Foxo1. Notably, β-cell dedifferentiation is heterogeneous, with distinct cells in the same islet exhibiting different stages of dedifferentiation. To understand the heterogeneity of β-cell dedifferentiation, we purified islets from β-cell-specific Foxo1 knockout mice and separated them by flow cytometry using an insulin promoter (Rip-Cre)-driven Rosa26 tdTomato reporter to select β-cells. Surprisingly, tdTomato-positive (β-) cells partitioned into two distinct clusters based on signal intensity. Both clusters were Foxo1-deficient. The subpopulation characterized by low levels of tdTomato expression (Tlow β-cells), increased from 2 to ~13% of the total β-cell population as animals aged from 3- to 24-months, and was absent in WT controls. Strikingly, this subpopulation was characterized by a compensatory increase of Foxo3 expression. To assess the function of Tlow β-cells, we performed glucose-stimulated insulin secretion assays on sorted pseudo-islets. Tlow β-cells exhibited enhanced glucose-dependent insulin secretion compared to Foxo1 knockout β-cells that failed to increase Foxo3 expression. Gene Ontology (GO) analyses of RNA-seq data revealed that the main difference between Foxo1 knockout cells without Foxo3 compensation and Tlow β-cells was in the oxidative phosphorylation and ATP synthesis-coupled electron transport pathways. This study illuminates β-cell heterogeneity in diabetic islets and suggests a role of Foxo3 compensation in the heterogeneity of β-cell dedifferentiation and in age-dependent changes of β-cell function.

Disclosure
J. Son: None. D. Accili: None.

Funding
National Institutes of Health (DK134848); National Institutes of Health (DK64819)
1752-P: Mechanistic Effects of Intermittent Hypoxia ?(IH) on? ß-Cells, Glucose Homeostasis, and Predisposition to Type 2 Diabetes (T2D)
Authors: BAKER TESS A. , ANDRADE LOUZADA NETO RUY , PUNJABI NARESH M. , BERNAL-MIZRACHI ERNESTO 
Published: June 2024

The capacity of pancreatic β-cells to adapt to insulin resistance or stress conditions is the major determinant of developing Type 2 diabetes (T2D). Obstructive sleep apnea (OSA), a prevalent disorder associated with T2D, causes chronic intermittent hypoxia (IH). The mechanisms through which OSA/chronic IH cause abnormalities in glucose levels and T2DM are not known. Mechanistic responses to hypoxia in other tissues involve alterations in AMPK and mTORC1 signaling, but how these alterations affect tissues responsible for glucose homeostasis, including β-cells, is not known. It was hypothesized that IH leads to alterations in glucose homeostasis by inducing β-cell function via upregulation of mTORC1 signaling in β-cells. To examine the role of IH in glucose homeostasis and β-cell function, we used a system to induce IH in both in vivo and in vitro models. The fractional inspired O2 between 21% and 5% in 30 second intervals (~ 60 episodes/hr), for 12hrs/day for 7, 14, and 28-days in C57B6J mice. IH resulted in improved glucose tolerance and insulin sensitivity. Evidence of hypoxia at the β-cell level was seen by an increase in a common target of hypoxia inducible factor (HIF1), adrenomedullin, and an increase of the Hypoxyprobe marker, pimonidazole. At the mechanistic level, β-cells from IH exposed mice and islets exposed to IH in vitro displayed increase in mTORC1 activation, via activation of its downstream target pS6(240). Taken together, the current evidence showed that IH can induce improvements in glucose tolerance and insulin secretion, and this was associated to augmented mTORC1 signaling.

Disclosure
T.A. Baker: None. R. Andrade Louzada Neto: None. N.M. Punjabi: None. E. Bernal-Mizrachi: None.

Funding
R01 DK073716/DK/NIDDK
1753-P: Alteration of Splice Type in Type 2 Ryanodine Receptor Causes Impaired Insulin Secretion in Mice
Authors: MAKINO MAI , UCHIYAMA TOMOKO , OSHIMA YU , DAIKOKU TAKIKO , YAMAMOTO YASUHIKO , OKAMOTO HIROSHI , NAKAMURA SHUHEI , TAKASAWA SHIN 
Published: June 2024

Increase of intracellular Ca2+ concentration is essential for glucose-induced insulin secretion. Type 2 ryanodine receptor (RyR2) is a Ca2+ release channel that mobilizes Ca2+ from the endoplasmic reticulum to the cytosol. Unlike RyR2 mRNA expressed in heart, RyR2 mRNA expressed in pancreatic β cells lacks exon 75, probably due to a unique splice donor site “gg” of intron 75 in RyR2 gene. We previously reported that the alteration of splicing in RYR2 caused impaired insulin biosynthesis in human 1.1B4 β cells. Here, to further investigate the significance of RyR2 alternative splicing in vivo, especially glucose-induced insulin secretion, we generated the homozygous genome-modified mice, named RyR2Ex75KI/Ex75KI, in which exon 75-containing RyR2 is expressed systemically including pancreatic β cells by using CRISPR/Cas9 system. Immunohistochemical analysis of pancreas from 15-week-old RyR2Ex75KI/Ex75KI and control wild-type (WT) mice revealed that the size of islets in RyR2Ex75KI/Ex75KI mice was almost the same as that in WT mice, while the insulin-positive area per islet was significantly decreased (0.44-fold, P=0.005). Isolated islets from 9- to 12-week-old mice of each genotype were stimulated by low (2.8 mmol/L) or high (20 mmol/L) glucose for 1 h and secreted insulin was measured by ELISA. Insulin secretion after low glucose treatment from RyR2Ex75KI/Ex75KI islets was significantly higher than that from WT islets (5.27-fold, P=0.019), and insulin secretion after high glucose stimulation was not increased (0.77-fold relative to low glucose stimulation). Intraperitoneal glucose tolerance test (2 g/kg) for 120 min on 14- to 19-week-old mice revealed that blood glucose levels did not differ between genotypes and serum insulin levels at 60-120 min after the glucose challenge were slightly higher in RyR2Ex75KI/Ex75KI mice. Taken together, our results suggest that the WT splice variant of RyR2 would have a crucial role in glucose-induced insulin secretion in vivo.

Disclosure
M. Makino: None. T. Uchiyama: None. Y. Oshima: None. T. Daikoku: None. Y. Yamamoto: None. H. Okamoto: None. S. Nakamura: None. S. Takasawa: None.

Funding
JSPS KAKENHI Grant Number JP21K15375