bluuebunny/crossref_metadata_2025 huggingface dataset:
1519-P: Role of Cyr61 in Palmitic Acid-Induced Insulin Resistance and Inflammation in Hepatocyte
Authors: HEO YUJUNG , JUNG KIM DAE , JIN KIM HAE , LEE NAMI , LEE KWANWOO , CHOI SUNG E.Y. , KANG YUP Y. , JIN HAN SEUNG , YOUNG JEON JA
Published: June 2023

Objective: Cysteine-rich protein 61 (Cyr61, also known as Cellular Communication Network Factor 1, CCN1) is involved in a variety of diseases, such as carcinoma, inflammation, and fibrosis. It was recently reported that Cyr61 was associated with nonalcoholic fatty liver disease. Here, we evaluated the effects of Cyr61 on hepatic inflammation and insulin resistance in HepG2 cells and examined the molecular mechanisms involved.

Methods: We treated HepG2 cells with palmitic acid (PA) and then evaluated insulin signaling pathway using immunoblotting. After treatment with PA, the pro-inflammatory cytokines, including IL-6, TNF-α, and IL-1β, and Cyr61 were assessed by RT-PCR and ELISA. To investigate the effects of Cyr61 on insulin resistance and inflammation, we used Cyr61 small interfering (si) RNA and anti-Cyr61 neutralizing antibodies. The Cyr61 siRNA were transiently transfected into HepG2 cells using Lipofectamine 2000.

Results: Compared to the control, PA reduced IR phosphorylation, IRS-1 (Tyr612) phosphorylation, AKT phosphorylation, and GSK-3α/β phosphorylation after insulin stimulation. PA stimulated NF-κB and JNK activation in a dose-dependent manner. PA significantly increased the expression and secretion of Cyr61 and pro-inflammatory cytokines. Interestingly, neutralization of Cyr61 reduced NF-κB and JNK signaling, which was increased by PA, and recovered insulin signaling. In addition, Cyr61-si RNA treatment reduced the mRNA expression of PA-induced IL-6, TNF-α and IL-1β, and decreased NF-κB and JNK signaling.

Conclusion: Inhibition of Cyr61 recovered insulin signaling and reduced inflammation in HepG2 cells. Cyr61 may play a role in PA-induced insulin resistance and inflammation in HepG2 cells.

Disclosure

Y.Heo: None. D.Kim: None. H.Kim: None. N.Lee: None. K.Lee: None. S.E.Y.Choi: None. Y.Y.Kang: None. S.Han: None. J.Jeon: None.

Funding

National Research Foundation of Korea (2020R1F1A1074019, 2021M3H1A104892211)
152-OR: The Infected Diabetic Foot—The MRSA Incidence, Conversion of Non-MRSA to MRSA Pathogens, and Reinfection in Soft Tissue and Bone Infections
Authors: SULUDERE MEHMET A. , KILLEEN AMANDA L. , CRISOLOGO PETER , LAVERY LAWRENCE A.
Published: June 2023

Aim: To evaluate the incidence of MRSA infection, re-infection, and the conversion of non-MRSA bacterial pathogens to MRSA in re-infections.

Methods: This was a post hoc analysis of 233 patients that participated in an RCT for moderate and severe diabetic foot infections with 12-month outcomes. We used bone culture and/or pathology to define osteomyelitis (OM). Soft tissue infections (STI) were defined based on negative bone biopsy or negative MRI. Moderate and severe infection was based on criteria of the International. Working Group on the Diabetic Foot infection classification. All subjects required surgery. We evaluated bacterial pathogens from bone and deep soft tissue from their initial infection and when there was re-infection. We defined conversion when a subject did not have MRSA in either their first OM or STI culture and had MRSA when there was re-infection. We used χ2 for comparison of clinical events, with alpha of <0.05.

Results: OM was present in 73.0% (n=170) of cases. MRSA incidence was 8.6% (n=20), with no difference between STI and OM (14.3% vs. 6.5%, p=0.06). Reinfection occurred in 29.2% (n=68), with no difference between STI and OM (36.5% vs. 26.5%, p=0.14). MRSA was seen in 29.4% (n=20) of the reinfections, with no difference between STI and OM (13.0% vs. 28.9%, p=0.16). Conversion to MRSA was seen in 14.7% (n=10), with no difference between STI and OM (4.3% vs. 20%, p=0.12). MRSA was 4.4 times more likely in re-infection compared to index infections (29.4% vs 8.6%, CI 2.2-8.9, p<0.01).

Conclusion: The incidence of MRSA is 4.4-fold higher after re-infection. The incidence of MRSA for the first infection (8.6%) was low. Re-infection with MRSA (29.4%) and conversion to MRSA (14.7%) were common. There was no difference seen in the incidence rates for reinfection, MRSA, reinfection with MRSA, and conversion to MRSA between patients with STI and OM.

Disclosure

M.A.Suludere: None. A.L.Killeen: Research Support; 3M/KCI, AstraZeneca, BioTissue surgical, Hologenix, LLC, Integra LifeSciences, Kent Imaging Inc., Microbion, PolarityTE, Inc., Smith+Nephew, Stark Enterprises, LLC, Xyken, VasoActiv, ViOptix. P.Crisologo: None. L.A.Lavery: Research Support; AstraZeneca, Tissue tech, American Diabetes Association, PolarityTE, Inc., Microbion, Jarvis, Integra Lifesciences Holdings Corp, Smith+Nephew.
1520-P: Metabolic Dysregulation in Probable Alzheimer’s Disease
Authors: READING CHRISTOPHER L. , AHLEM CLARENCE , PALUMBO JOSEPH M. , TESTA MARCIA A. , SIMONSON DONALD C.
Published: June 2023

Insulin resistance, T2D, and chronic inflammation increase risk of developing mild cognitive impairment and Alzheimer’s disease (AD). We report here baseline data from a multicenter, randomized, placebo-controlled Phase 3 study (NCT04669028) in patients with mild to moderate AD evaluating the effects of NE3107, an oral small molecule, blood-brain permeable anti-inflammatory insulin sensitizer that binds extracellular signal-regulated kinase. Inclusion criteria are diagnosis and progression of AD, supportive brain scan and Hachinski scale to exclude vascular dementia, Clinical Dementia Rating (CDR) score of 1-2, and Mini Mental State Exam (MMSE) score of 14-24. Primary outcomes are changes in cognition and function from baseline to 30 wks. Secondary outcomes include changes in neuropsychological deficits, functional performance, and regulation of glycemia. Aβ+ subjects were older and had worse MMSE, ADAS-Cog12 and AD Composite Scores than Aβ-patients, but had less evidence of inflammation (lower CRP) and less insulin resistance (lower fasting glucose, less IFG and T2D, lower fasting insulin and HOMA2-IR, and less hypertension) (Table). Metabolic dysregulation (elevated C1q, increased CGM mean and MAGE, increased cholesterol, triglycerides, and waist-hip ratio) was also observed independent of Aβ and APOEε4 status. Inflammation and insulin resistance may contribute to AD even in the absence of classical risk markers for AD.

Disclosure

C.L.Reading: Employee; BioVie, Inc. C.Ahlem: Employee; Biovie, Inc. J.M.Palumbo: Employee; BioVie, Zynerba, Other Relationship; Merck Sharp & Dohme Corp. M.A.Testa: Stock/Shareholder; Phase V Technologies, Inc. D.C.Simonson: Stock/Shareholder; Phase V Technologies, Inc., GI Windows.
1525-P: Ventromedial Hypothalamic Nucleus Subset Stimulates Tissue Thermogenesis via Preoptic Outputs
Authors: ELMENDORF ANDREW J. , MAHLER CONNOR A. , LORENTZ BETTY , FLAK JONATHAN
Published: June 2023

Changes in energy status ignite neural circuits that maintain body weight by engaging peripheral mechanisms that control energy expenditure; obesity results for when these responses are no longer sufficient. The key neural circuits that stimulate energy expenditure have not yet been established, but previous research has identified several critical sites (e.g. preoptic area (POA) and ventromedial hypothalamus (VMN)) that could be part of an interconnected system that controls tissue thermogenesis, which is essential for body weight control. Activating SF1-cre VMN cells in male diet-induced obese mice reduces body fat by 25% in 72 hours. This function is likely mediated at least in part by release of the peptide pituitary adenylate cyclase-activating polypeptide (PACAP), since knockout of PACAP in the VMN induces obesity at thermoneutrality (30C) and suppresses temperature above both the brown and beige adipose tissue in response to feeding. Because some VMN cells densely project to the POA, we hypothesized that VMN PACAP cells activate tissue thermogenesis via preoptic outputs. We placed temperature-sensing microchips above a traditional brown (interscapular brown adipose tissue (iBAT) and beige (inguinal white adipose tissue (iWAT) adipose tissue in Adcyap1(gene for PACAP)cre mice with DIO-ChR2 in the VMN and fiber optic implants in two major VMN outputs: the POA and the bed nucleus of the stria terminalis (BST). Activating VMN fibers in the POA that contain PACAP in both male and female mice, but not the BST, increased iBAT and iWAT temperature, and the effect was most robust when the mice were fasted. In summary, these data indicate that VMN PACAP connections with the POA is important for the induction of tissue thermogenesis, particularly when feeding conditions change. VMN PACAP, as well as associated signaling targets, are critical components to energy balance by activating adipose tissue mechanisms that stimulate energy expenditure.

Disclosure

A.J.Elmendorf: Other Relationship; Eli Lilly and Company. C.A.Mahler: Stock/Shareholder; AbbVie Inc., Pfizer Inc., AstraZeneca. B.Lorentz: Research Support; Eli Lilly and Company. J.Flak: Research Support; Eli Lilly and Company.

Funding

American Diabetes Association (Pathway 17-INI-15 to J.F.); Ralph W. and Grace M. Showalter Research Trust; Indiana University; Indiana Biosciences Research Institute
1527-P: Anorexia Induced by the Central Action of Fibroblast Growth Factor 1 (FGF1) Is Dependent on Reduced GABA Receptor Activation
Authors: SCARLETT JARRAD M. , ALONGE KIMBERLY M. , PHAN BAO ANH N. , MORTON GREGORY J. , SCHWARTZ MICHAEL W.
Published: June 2023

Previously, we reported that in multiple rodent models of type 2 diabetes, remission of hyperglycemia lasting for weeks can be induced by a single intracerebroventricular (icv) injection of FGF1. This effect is accompanied by a potent but transient anorexic response that is sufficiently robust as to hinder efforts to translate these findings towards the clinic. To understand the mechanism underlying FGF1-induced anorexia, we considered 1) our recent finding that icv FGF1 induces acute and sustained inhibition of hypothalamic AgRP neurons, and 2) prior work showing that parabrachial nucleus that express calcitonin gene-related peptide (PBNCGRP neurons) are both highly anorexigenic and tonically inhibited by GABAergic projections from AgRP neurons. We therefore hypothesized that FGF1-induced anorexia involves activation PBNCGRPneurons arising from reduced GABAergic input. Consistent with this hypothesis, we report that PBNCGRPneurons are robustly activated following icv FGF1 injection (based on c-Fos staining) via a mechanism that appears to be indirect, since the c-Fos induction is not associated with FGF receptor (FGFR) activation (detected by pERK staining in the PBN). We next asked whether the anorexic response to icv FGF1 administration can be blunted by systemic administration of a GABAA receptor agonist. Consistent with this hypothesis, we found that continuous subcutaneous infusion of the GABAA receptor agonist Bretazenil blunts the anorexic response to icv FGF1 injection by ~50% at a dose that has no effect intake in control mice. Similarly, the effect of FGF1 to induce c-Fos in the PBN was largely blocked by Bretazenil, and our preliminary findings indicate that CGRP neurons are among those in which this effect occurred. Together, these data suggest that FGF1-induced anorexia results from reduced GABAergic inhibition of PBNCGRP neurons.

Disclosure

J.M.Scarlett: None. K.M.Alonge: None. B.N.Phan: None. G.J.Morton: Research Support; Novo Nordisk A/S. M.W.Schwartz: Consultant; NodThera, Research Support; Novo Nordisk A/S.

Funding

U.S. Department of Defense (PRMRP W81XWH-21-1-0635); National Institutes of Health (DK083042)
1530-P: Retinoic Acid Signals in the Hypothalamus Regulate Energy Balance in a Sexually Dimorphic Manner
Authors: YU MENG , YANG YONGJIE , HE YANG , BEAN JONATHAN , LIU HAILAN , WANG CHUNMEI
Published: June 2023

Retinoic acid (RA) is the active metabolite of Vitamin A (Vit-A), and both Vit-A and RA are essential micronutrients for life. Vit-A-deficient mice are leaner than Vit-A-sufficient mice fed with either chow or high-fat-diet (HFD), implying the role of RA in promoting body weight gain. Global loss of key RA synthesis enzyme retinaldehyde dehydrogenase-1 (Aldh1a1) or RA receptor retinoid X receptor gama (RXRγ) both protects mice from diet-induced obesity (DIO). However, the metabolic roles of central RA, especially the endogenously RA synthesized in the hypothalamus, are unclear. Both the RA synthesizing enzymes including Aldh1a1 and RA receptors including RXRγ and retinoic acid receptor beta (RARβ), are accumulated in the hypothalamus. We found that loss of RXRγ or RARβ in pro-opiomelanocortin (POMC)-expressing neurons in the arcuate nucleus of hypothalamus (ARH) produced lean phenotypes in a sexually dimorphic manner. In particular, loss of RXRγ in POMC neurons reduce body weight and food intake only in chow-fed female mice, but not in male mice; meanwhile, loss of RARβ in in POMC neurons reduce body weight in both sexes, with reduced food intake in male mice but not in female mice. Independent of body weight, glucose tolerance and insulin tolerance were not changed by POMC specific deficiency of either RXRγ or RARβ in either sex. Since RA can bind to both RXRγ and RARβ, and RA can be locally synthesized in the hypothalamus using Vit-A metabolites as substrates, these results support that RA acts on RXRγ and RARβ in POMC neurons to regulate energy balance in a sexually dimorphic manner. These studies will advance our understanding about the physiology of body weight/glucose balance regulated by RA and RXR or RAR complexes, which will facilitate the characterization of the current RA or RXR-based therapies and provide novel targets for anti-obesity/diabetes therapies.

Disclosure

M.Yu: None. Y.Yang: None. Y.He: None. J.Bean: None. H.Liu: None. C.Wang: None.
154-OR: Metabolomics Analysis Reveals Links between Stress Hyperglycemia and Underlying Differences in Branched-Chain Amino-Acid Metabolism and Microbiome–Host Interactions
Authors: ABRAHAM AMALIA , SMITH MATTHEW R. , PEREZ-GUZMAN MIREYA , ZAHEDI TAJRISHI FARBOD , GUERRERO ARROYO LIZDA I. , CHAKRAGIRI AMSHUMANTH , SAM VARGHESE JITHIN , PASQUEL FRANCISCO J.
Published: June 2023

The mechanisms that lead to stress-hyperglycemia are poorly understood. We examined metabolic signatures associated with stress-hyperglycemia in patients without diabetes undergoing cardiac surgery. We enrolled patients without diabetes [BG ≤125mg/dl and HbA1c<6.5%] undergoing CABG surgery and compared those with stress hyperglycemia (“High”, mean glucose >140 or glucose >180mg/dl) vs those with preserved glucose metabolism (“Low”). Utilizing untargeted LCMS-derived high-resolution metabolomics (HRM) analysis we examined metabolites and metabolic pathways associated with incident stress hyperglycemia. Metabolic pathways were identified from HILIC positive and Reverse Phase C18 analysis, with metabolites mapped to Kyoto Encyclopedia of Genes and Genomes (KEGG) human pathways. A total of 36 patients (age: 62.7 years, 83% male, HbA1c 5.5%) underwent CABG surgery. Nine patients developed stress hyperglycemia immediately after starting surgery and showed differences in branched-chain amino acids (BCAA, e.g., methyl-oxopentanoate), lipid metabolism (e.g., diacylglycerols), and microbiome metabolism (e.g., linoleate), figure. This analysis reveals links between stress-hyperglycemia and BCAA, and lipid metabolism, and microbiome-host interactions among nondiabetic patients undergoing cardiac stress.

Disclosure

A. Abraham: None. M.R. Smith: None. M. Perez-Guzman: None. F. Zahedi Tajrishi: None. L.I. Guerrero Arroyo: None. A. Chakragiri: None. J. Varghese: None. F.J. Pasquel: Consultant; Dexcom, Inc., Medscape. Research Support; Dexcom, Inc., Ideal Medical Technologies.

Funding

National Institutes of Health (K23GM128221)
1547-P: The Differential Effect of Glucagon-Like Peptide-1 Receptor Blockade on Glucose Metabolism in People With and Without Type 2 Diabetes
Authors: WELCH ANDREW A. , FARAHANI RAHELE A. , ZEINI MAYA , EGAN AOIFE M. , LAURENTI MARCELLO C. , COBELLI CLAUDIO , DALLA MAN CHIARA , VELLA ADRIAN
Published: June 2023

Glucagon-Like Peptide-1 (GLP-1) is present within the islet but the effects of GLP-1 Receptor (GLP1R) blockade on islet function in humans remains unknown. To address this, we studied 12 nondiabetic individuals (54 ± 2 years, 33 ± 1 kg/m2) and 11 people with type 2 diabetes (DM2 - 58 ± 2 years, 34 ± 2 kg/m2) on 2 occasions in random order. On each occasion, after an overnight fast, [3-3H] glucose was used to measure glucose turnover during fasting and a hyperglycemic clamp (~9 mmol/l) using the tracer dilution technique. On one occasion exendin-9,39 (300pmol/kg/min) was infused to block GLP1R, while on the other saline was infused. Exendin-9,39 increased fasting glucose concentrations in those without (4.6 ± 0.4 vs. 5.5 ± 0.1 mmol/l, saline vs. exendin-9,39 respectively, p = 0.04) and in those with DM2 (7.3 ± 0.5 vs. 8.3 ± 0.6 mmol/l, p = 0.03). Fasting islet hormone concentrations were unchanged, but inappropriate for the higher fasting glucose observed during exendin-9,39 infusion. The same pattern was seen in people with DM2 except that fasting glucagon concentrations increased (8.3 ± 0.5 vs. 10.2 ± 0.6 pmol/l, p < 0.01) and remained elevated throughout hyperglycemia (4.7 ± 0.4 vs. 7.7 ± 0.6 pmol/l, p < 0.02). Insulin secretion rate calculated by deconvolution of C-peptide concentrations was also decreased in DM2 (0.54 ± 0.08 vs. 0.51 ± 0.08 nmol/min, p = 0.02). Consequently, suppression of endogenous glucose production by hyperglycemia was impaired in people with DM2 (2.9 ± 0.4 vs. 5.7 ± 0.3 μmol/kg/min, p < 0.01). Intriguingly, 1st phase response to hyperglycemia was decreased in those without DM2 (3.5 ± 0.6 vs. 2.5 ± 0.5 nmol per 10 min, p = 0.04). These data show that in humans, GLP1R blockade impairs fasting α- and β-cell function resulting in fasting hyperglycemia. Subtle effects are also present in response to hyperglycemia. This implies that intra-islet GLP1R activation sustains islet responses to glucose and it does so to a greater degree in people with DM2.

Disclosure

A.A. Welch: None. R.A. Farahani: None. M. Zeini: None. A.M. Egan: None. M.C. Laurenti: None. C. Cobelli: None. C. Dalla Man: Research Support; Sanofi-Aventis Deutschland GmbH, Becton, Dickinson and Company. A. Vella: Other Relationship; Novo Nordisk. Advisory Panel; Rezolute, Inc. Consultant; Crinetics Pharmaceuticals, Inc., Hanmi Pharm. Co., Ltd., Zealand Pharma A/S.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (R01DK126206)
1550-P: A Gain-of-Function Maturity-Onset Diabetes of the Young (MODY)–Associated TALK1 Mutation Impairs Glucose Metabolism in Mice
Authors: TSAI WEN-HAO , YANG SHI-BING
Published: June 2023

A Leu substitution with Pro at position 114 (L114P) of TALK1 K+ channels has recently been identified in a MODY (maturity-onset-diabetes-of-the-young) family. Previous in vitro studies have shown this gain-of-function TALK1-L114P mutant may attenuate Ca2+ homeostasis and inhibit insulin secretion; nevertheless, how this mutant induces diabetes in vivo remains elusive. In this study, we have generated a transgenic mouse line that carries a TALK1-L114P mutation. About three-quarters of TALK1L/P and TALK1P/- mice died within ten days after birth due to hyperglycemia. Interestingly, those survival mice till adulthood exhibited diverse levels of glucose intolerance with islet morphology that is commonly observed in patients with type 2 diabetes. Electrophysiological recording further indicated that only a portion of the beta cells is glucose responsive, and high glucose challenge often yielded in low-frequency action potential bursting. According to our results, we hypothesized that despite the augment of membrane K+ conductance by the TALK1-L114P channel, high glucose might still be enough to depolarize beta cells and generate action potential bursting. This dampened beta cell excitation may result in a weakened Ca2+ influx and insufficient insulin secretion to cause glucose intolerance. In conclusion, this study has revealed a vital role of the TALK1 channel in regulating glucose homeostasis and a plausible diabetogenic mechanism of TALK1-L114P mutation.

Disclosure

W.Tsai: None. S.Yang: None.

Funding

National Science and Technology Council, Taiwan (111-2320-B-001-008-MY3)
1555-P: Novel Imaging Platform Highlights the Disconnect between ß-Cell Mass and Glucose Control in the Onset of Type 1 Diabetes
Authors: CRAS-MÉNEUR CORENTIN , SEELEY RANDY J. , ARVAN PETER
Published: June 2023

The age of onset of Type 1 Diabetes (T1D) presents considerable variation from patient to patient. Some become insulin dependent in a just few weeks, while others may take months or years. In either, immune system-β-cell interactions conspire to lead to loss of β-cells and insulin secretion. The molecular and cellular events involved have been the focus of intense research efforts, but most longitudinal studies during the onset of T1D have been limited to biomarkers (circulating autoantibodies, C-peptide⋯), without direct β-cell assessment. Despite data indicating that patients can retain functional β-cells years after the onset of the disease, one school of thought is that there is a precipitous loss of β-cells just preceding the time of clinical onset, triggering the hyperglycemia observed in T1D patients. A counter-view supported by recent studies suggests that insulin secretion is reduced even before β-cell loss. These assessments are traditionally performed through histo-morphometry. The process is time-consuming, prone to errors and costly. Using an NOD line with a SfGFP reporter attached to the C-peptide, we have designed a platform allowing the in toto imaging of β-cell mass in a model of T1D. After a 15-minute IPGTT to capture the peak of insulin secretion, pancreata were harvested and imaged on a cohort of animals at a time of early onset of T1D. A comparison of classical histo-morphometry and in toto imaging revealed a tight correlation between both approaches. Using the new platform allowed the rapid classification of large cohorts of animals based on the β-cell mass and glucose response. The results highlighted a significant disconnect between mass and function in a subset of mice: Some animals presenting near-normal mass while being glucose intolerant while others displaying a drastically reduced mass but still responding normally to a glucose challenge. These findings emphasize the role of islet dysfunction during the onset of T1D even before β-cell death.

Disclosure

C.Cras-méneur: None. R.J.Seeley: Board Member; Fractyl Health, Inc., Consultant; Novo Nordisk, Eli Lilly and Company, Research Support; Novo Nordisk, Fractyl Health, Inc., AstraZeneca, Eli Lilly and Company. P.Arvan: None.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (P30DK020572)
1561-P: Dietary Proteins Impact Glucose Tolerance and Hepatic Insulin Resistance in Mice through Modulation of the Urea Cycle
Authors: BÉGIN FRÉDÉRIC , CARON ALEXANDRE , MARETTE ANDRE
Published: June 2023

We recently reported that dietary proteins (DP) modulate diet-induced obesity and insulin resistance in mice (Nat Commun 12: 3377, 2021). We posit that these metabolic alterations are caused by differential activation of the hepatic urea cycle in response to different amino acid (AA) compositions and total nitrogen load.

Objective: To test whether DP sources alter hepatic metabolism and insulin resistance through the urea cycle.

Methods: Metabolic phenotypes, hepatic urea cycle and insulin resistance were measured in mice fed low-fat, low-sucrose (LFLS) or high-fat, high-sucrose (HFHS) diets containing either pork (PP), soy (SP) or casein (CP) protein for 12 weeks. Based on their AA composition, PP had the highest nitrogen load, followed by SP and CP.

Results: When compared to SP and CP, feeding PP to HFHS mice induced more glucose intolerance which was correlated with higher post-prandial AA-derived nitrogen load in the portal vein. PP feeding in HFHS mice induced hepatic insulin resistance, revealed by impaired insulin-induced Akt phosphorylation on Ser473. Mice fed the LFLS diet were, however, protected from PP-induced glucose intolerance and insulin resistance, and this was associated with robust increase in the protein levels of urea cycle enzymes (CPS1, OTC) in the liver. In starked contrast, induction of urea cycle enzymes was blunted in the liver of PP-fed HFHS mice. PP feeding also increased the expression of inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS) as showed by DHE staining of liver sections.

Conclusion: Dietary PP increases total nitrogen load activating the urea cycle, which may protect against metabolic dysfunction and hepatic insulin resistance in LFLS mice. This protective mechanism is lost in PP-fed HFHS mice, likely by downregulation of urea cycle activity, when the liver is overloaded with dietary fat. iNOS induction could be acting as an alternative nitrogen handling pathway, causing a build-up of mitochondrial ROS.

Disclosure

F.Bégin: None. A.Caron: None. A.Marette: Advisory Panel; Valbiotis, Amancia, Plexus, Acasti.
1563-P: Hepatic PHD3 Stimulates Gluconeogenesis and Aggravates Hyperglycemia and Type 2 Diabetes by Hydroxylating CRTC2 at Pro129 and Pro615
Authors: XUE YAQIAN , CUI AOYUAN , WEI SHUANG , MA FENGGUANG , LIU ZHENGSHUAI , FANG XIA , LI WENJING , LIU YUXIAO , CAI GENXIANG , SU WEITONG , ZHAO JIUXIANG , GAO CHENLIN , WEN JIAN , XU YONG , FU WENGUANG , FANG JING C. , LI YU
Published: June 2023

Hepatic gluconeogenesis is critical for metabolic adaption in response to fasting, and its abnormal elevation contributes to the pathogenesis of hyperglycemia and type 2 diabetes. However, whether and how protein hydroxylation regulates hepatic gluconeogenesis and glucose metabolism remains largely unknown. Here we report that PHD3 is identified as a fasting-induced factor and regulates hepatic gluconeogenesis through interaction and hydroxylation of CRTC2. Pro129 and Pro615 hydroxylation of CRTC2 following PHD3 activation is necessary for its nuclear translocation and association with CREB, and enhanced binding to promoters of gluconeogenic target genes in response to fasting or the cAMP activator forskolin. CRTC2 hydroxylation-stimulated gluconeogenic gene expression is independent of SIK-mediated phosphorylation of CRTC2. Liver-specific knockout of PHD3 (PHD3 LKO) mice or prolyl hydroxylase-deficient knockin mice with alanine mutation in PHD3 at Pro196 (PHD3 KI) show significant attenuated gluconeogenic genes, glycaemia and hepatic capacity to produce glucose during fasting or fed with high-fat, high-sucrose diet. The efficacies of glucagon or adenylyl cyclase activator forskolin on stimulating the expression of gluconeogenic enzymes, such as PEPCK and G6Pase, and on glucose output are abolished in PHD3-/- mouse primary hepatocytes. Importantly, Pro615 hydroxylation of CRTC2 by PHD3 is increased in livers of fasted mice, diet-induced insulin resistance or genetically obese ob/ob mice and humans with diabetes. Together, these findings increase our understanding of the molecular mechanisms linking protein hydroxylation to gluconeogenesis under physiological and insulin resistant conditions, and may offer therapeutic potential for treating sustained gluconeogenesis, hyperglycemia and type 2 diabetes.

Disclosure

Y.Xue: None. W.Su: None. J.Zhao: None. C.Gao: None. J.Wen: None. Y.Xu: None. W.Fu: None. J.C.Fang: None. Y.Li: None. A.Cui: None. S.Wei: None. F.Ma: None. Z.Liu: None. X.Fang: None. W.Li: None. Y.Liu: None. G.Cai: None.

Funding

National Key R&D Program of China (2019YFA0802502); National Natural Science Foundation of China (81925008, 82073061, 82170587, 32100943); Ministry of Science and Technology of China (2020YFA0803301); Open Project Program of Metabolic Vascular Diseases Key Laboratory of Sichuan Province (2022MVDKL-K2); Shandong Natural Science Foundation (ZR2020MH206); China Postdoctoral Science Foundation (2021M693273)
1565-P: Relationship between Glycemic Control, Body Weight, and Nonalcoholic Fatty Liver Disease in Patients with Type 1 Diabetes
Authors: DHAVER SHILTON E. , SALAH TAREQ , AL-BADRI MARWA , KIBAA KARIM , KHATER ABDELRAHMAN , MCCARRAGHER RYAN , AL-ROOMI FATIMAH , DEMATTOS LILY , HAMDY OSAMA
Published: June 2023

Increased body weight is a common risk factor for nonalcoholic fatty liver disease (NAFLD). Although the prevalence of overweight and obesity among patients with type 1 diabetes (T1D) is rising, most patients are still lean. Currently, little is known about the relationship between glycemic parameters, body weight and NAFLD in patients with T1D.

In this study, we evaluated glycemic parameters in 200 participants with T1D (mean age 46.9±16.5 years, 55.5% females, mean diabetes duration 27.4±15.7 years, mean BMI 26.9±5.0 kg/m2) who underwent screening for NAFLD. We used transient elastography to measure controlled attenuation parameter (CAP) as an indicator of hepatic steatosis, and liver stiffness measurement (LSM) as an indicator of hepatic fibrosis. We assessed glycemic parameters by measuring A1C and collecting 3 months of continuous glucose monitoring (CGM) data.

CAP score was found to be positively correlated with A1C (p=0.009) and BMI (p<0.001). Participants with NAFLD (CAP≥274 dB/m) had significantly higher A1C (p=0.025). Using CGM parameters, CAP positively correlated with average blood glucose (p=0.029) and Glucose Management Indicator (GMI) (p=0.008). CAP positively correlated with coefficient of glucose variability (CV) only in lean individuals (BMI≤25 kg/m2) (p=0.031), suggesting a link between blood glucose variability and hepatic steatosis in the absence of overweight or obesity. LSM score positively correlated with BMI (p<0.001), but not with A1C or CGM parameters.

We conclude that poor glycemic control is associated with hepatic steatosis while high BMI is associated with increased risk of hepatic fibrosis in patients with T1D. Blood glucose variability is particularly associated with hepatic steatosis in lean patients with T1D. These results may suggest the need of evaluating uncontrolled patients with T1D for NAFLD, specifically those with high BMI and those with high glucose variability.

Disclosure

S.E.Dhaver: None. T.Salah: None. M.Al-badri: None. K.Kibaa: None. A.Khater: None. R.Mccarragher: None. F.Al-roomi: None. L.Demattos: None. O.Hamdy: Advisory Panel; Abbott Nutrition, Nemaura Medical, L-Nutra Inc., Twin Health, Consultant; Sanofi, Research Support; Novo Nordisk, Eli Lilly and Company, Gilead Sciences, Inc., Stock/Shareholder; Healthimation.
1566-P: The TM6SF2 rs58542926 Polymorphism Dissociates Hepatocellular Lipids from Insulin Resistance in Recent-Onset Type 2 Diabetes
Authors: BÓDIS KÁLMÁN , BOMBRICH MARIA , SCHÖN MARTIN , KNEBEL BIRGIT , ZAHARIA OANA P. , BÖNHOF GIDON J. , KARUSHEVA YANISLAVA , KUPRIYANOVA YULIYA , KOTZKA JORG , GUTHOFF RAINER , SCHRAUWEN-HINDERLING VERA , AL-HASANI HADI , BURKART VOLKER , SZENDROEDI JULIA , WAGNER ROBERT , MARKGRAF DANIEL F. , RODEN MICHAEL
Published: June 2023

Increased hepatocellular lipid content (HCL) is generally linked to insulin resistance, which contributes to greater risk of type 2 diabetes and cardiovascular complications. Conversely, a single-nucleotide polymorphism (TM6SF2EK; rs58542926) in the transmembrane 6 superfamily member 2 gene has been associated with nonalcoholic fatty liver disease (NAFLD), but lower cardiovascular risk. Thus, this case-control study tested the role of this polymorphism for tissue-specific insulin sensitivity during the early course of diabetes. Males with recent-onset type 2 diabetes with (TM6SF2EK: n=16) or without (TM6SF2EE: n=16) the heterozygous TM6SF2 polymorphism of similar age and BMI, underwent Botnia-clamps with [6,6-2H2]glucose to measure whole-body, hepatic and adipose tissue insulin sensitivity. HCL and liver fibrosis were assessed with 1H-magnetic resonance spectroscopy and non-invasive tests (FIB4, APRI, AST/ALT), respectively. A subset of both groups (n=24) was re-evaluated after 5 years. Despite doubled HCL, TM6SF2EK had similar hepatic and adipose tissue insulin sensitivity and even 27% higher whole-body insulin sensitivity than TM6SF2EE. The novel diabetes endotypes were equally distributed among both groups. After 5 years, whole-body insulin sensitivity, HCL and liver fibrosis indices were similar, while adipose tissue insulin sensitivity decreased by 87% and 55% both in TM6SF2EK and TM6SF2EE and circulating triacylglycerol increased in TM6SF2EE only. The TM6SF2 gene polymorphism rs58542926 dissociates ectopic fat content from insulin resistance in recent-onset type 2 diabetes, which is however attenuated by disease duration. This suggests that diabetes-related metabolic alterations dominate over the effects of the TM6SF2 gene polymorphism during the early course of diabetes and NAFLD.

Disclosure

K.Bódis: None. R.Guthoff: Other Relationship; Alimera, Bayer Inc., Novartis, Allergan. V.Schrauwen-hinderling: None. H.Al-hasani: None. V.Burkart: None. J.Szendroedi: None. R.Wagner: Advisory Panel; Daiichi Sankyo, Speaker's Bureau; Novo Nordisk, Sanofi. D.F.Markgraf: Employee; Boehringer Ingelheim Pharma GmbH&Co.KG. M.Roden: Advisory Panel; Eli Lilly and Company, Consultant; TARGET PharmaSolutions, Inc., Research Support; Boehringer-Ingelheim, Novo Nordisk, Novartis, Sanofi. M.Bombrich: None. M.Schön: None. B.Knebel: None. O.P.Zaharia: None. G.J.Bönhof: None. Y.Karusheva: None. Y.Kupriyanova: None. J.Kotzka: None.
1567-P: Hepatic ALKBH5 Regulation of Glucose and Lipid Metabolism
Authors: AAMODT KRISTIE , POLAY MADISON , SALERNO GONZALES VALERIA R. , KULKARNI ROHIT
Published: June 2023

Obesity is a worsening global health crisis leading to increased risk of long-term complications such as type 2 diabetes (T2D), nonalcoholic steatohepatitis (NASH), dyslipidemia and cardiovascular disease. Identifying novel molecular mechanisms regulating the connection between obesity, hepatic insulin resistance and progression of NASH is critical to develop new therapeutic options for these patients. Previous work has shown that reversible N6-methyladenosine (m6A) RNA methylation patterns are altered in and regulate metabolic disease in the pancreatic beta cell and liver. However, these studies have primarily focused on the m6A writer proteins that direct placement of m6A methyl groups, while our study explores the role of m6A eraser protein AlkBH5 in regulating metabolic pathways in the liver.

To test the hypothesis that hepatic ALKBH5 is required to maintain normal glucose homeostasis, insulin sensitivity and lipid metabolism under physiologic conditions and in response to metabolic stress we used liver-specific Alkbh5 knockout (A5KO) mice and evaluated changes in weight gain, body composition, glucose tolerance, insulin sensitivity, fasting insulin levels, and gluconeogenesis in response to a chow versus Western diet (WD). In physiologic conditions (chow), A5KO mice have decreased glucose tolerance with no other significant phenotypic changes compared to controls. Exposure to metabolic stress (WD) caused (1) greater weight gain with increased visceral fat in control compared to A5KO mice, (2) decreased glucose tolerance compared to chow in both genotypes, (3) decreased glucose mobilization in A5KO mice on WD compared to chow, with no significant differences in controls, and (4) no significant differences in global insulin sensitivity. These studies demonstrate that A5KO mice are protected against weight gain upon exposure to metabolic stress with decreased glucose tolerance and mobilization compared to controls, establishing a role for hepatic ALKBH5 in regulating glucose and lipid metabolism.

Disclosure

K.Aamodt: None. M.Polay: None. V.R.Salerno gonzales: None. R.Kulkarni: Advisory Panel; Novo Nordisk, Inversago, Biomea Fusion, Inc., REDD Pharma, Research Support; Inversago.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (5T32DK007699-39, 5T32DK007260-45); Pediatric Endocrine Society
1568-P: Identification of Stage-Specific Hepatocytes That Contribute to Nonalcoholic Steatohepatitis Progression
Authors: XIAO YANG , ZHU KUN , LIU YIFAN , LAZAR MITCHELL A.
Published: June 2023

Current therapeutic strategies for treating an advanced form of nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), have failed to alleviate liver fibrosis, which is a devastating feature leading to hepatic dysfunction. To identify potential novel therapeutic targets, we integrated single-nucleus transcriptomics and epigenomics to characterize all major liver cell types during the progression from nonalcoholic fatty liver (NAFL) to NASH in mice and humans. We found that the hepatocyte trajectory switched from metabolic adaptation to cell adhesion and migration when the NAFLD stage transited from NAFL to NASH. The trajectory switch was conserved between mouse and human. The hepatocyte trajectory leading to NASH was enriched for a receptor tyrosine kinase, EphB2. The transcription of EphB2 in hepatocytes was activated by Notch signaling pathway and sufficient to induce cell-autonomous inflammatory response in mouse and human induced pluripotent stem cell (hiPSC) derived-hepatocytes. EphB2 loss-of-function specifically in hepatocytes ameliorated inflammation and fibrosis in mouse models of NASH. Thus, NASH-stage specific hepatocytes were demarcated by EphB2 and may serve as a potential therapeutic target.

Disclosure

Y. Xiao: None. K. Zhu: None. Y. Liu: None. M.A. Lazar: Board Member; Pfizer Inc. Consultant; Novartis. Board Member; Flare Therapeutics, Inc. Consultant; Third Rock Ventures, Inc, Madrigal Pharmaceuticals, Inc.

Funding

American Heart Association (827529); National Institutes of Health (R01DK125573)
1569-P: Lysophosphatidic Acid Mediates Inflammation in Liver and White Adipose Tissue in a Rat Model of 1-acyl-sn-glycerol-3-phosphate Acyltransferase 2 Deficiency
Authors: SAKUMA IKKI , GASPAR RAFAEL C. , LUUKKONEN PANU , KAHN MARIO , MURRAY SUE , SAMUEL VARMAN , PETERSEN KITT , SHULMAN GERALD I.
Published: June 2023

AGPAT2 (1-acyl-sn-glycerol-3-phosphate acyltransferase 2) converts lysophosphatidic acid (LPA) into phosphatidic acid (PA) and mutations of the AGPAT2 gene are responsible for the most common form of congenital generalized lipodystrophy (CGL) which leads to diabetes and steatohepatitis. The underlying mechanism by which AGPAT2 deficiency leads to these abnormalities has not been elucidated. We explored this question using an antisense oligonucleotide (ASO) to knock down expression of AGPAT2 in liver and white adipose tissue (WAT) of adult male SD rats. AGPAT2 ASO treatment induced lipodystrophic features in which adipose and hepatic inflammation were associated with increased LPA content in WAT (Control ASO=0.4 ± 0.1 nmol/g tissue; AGPAT2 ASO=0.8 ± 0.4, P<0.05) and liver (Control ASO=2.7 ± 0.4 nmol/g tissue; AGPAT2 ASO=4.2 ± 0.9, P<0.01) whereas PA content was unchanged. We hypothesized that increased LPA content may lead to inflammation in these tissues. We tested if either a controlled-release mitochondrial protonophore (CRMP) or an ASO against glycerol-3-phosphate acyltransferase, mitochondrial (GPAM) would reduce LPA content and inflammation in these tissues in AGPAT2 ASO treated rats. CRMP treatment (20 mg/[kg-day]) primarily prevented LPA accumulation in WAT (Control ASO=0.4 ± 0.1 nmol/g tissue; AGPAT2 ASO=0.9 ± 0.1; AGPAT2 ASO+CRMP=0.6 ± 0.1) (AGPAT2 ASO vs AGPAT2+CRMP P<0.05) and prevented WAT inflammation. In contrast GPAM ASO treatment primarily prevented hepatic LPA accumulation (Control ASO=3.6 ± 0.4 nmol/g tissue; AGPAT2 ASO=4.8 ± 0.2; AGPAT2+GPAM ASO=2.7 ± 0.4) (AGPAT2 ASO vs AGPAT2+GPAM ASO P<0.01) and prevented hepatic inflammation.

Conclusion: These results demonstrate a key role of LPA acid in mediating inflammation in liver and WAT in AGPAT2 deficient animals and identify novel therapeutic targets to treat CGL in patients with AGPAT2 deficiency.

Disclosure

I.Sakuma: None. R.C.Gaspar: None. P.Luukkonen: None. M.Kahn: None. S.Murray: Employee; Ionis Pharmaceuticals. V.Samuel: None. K.Petersen: Advisory Panel; Novo Nordisk, Research Support; Merck Sharp & Dohme Corp., Gilead Sciences, Inc. G.I.Shulman: Consultant; Novo Nordisk, DiCerna Pharmaceuticals, Inc., Bayer Consumer Care AG, Kriya Therapeutics, Arrowhead Pharmaceuticals, Inc., ESPERION Therapeutics, Inc., Other Relationship; AstraZeneca, Merck & Co., Inc., Janssen Research & Development, LLC, iMetabolic Biopharma Corporation, Maze Therapeutics, 89bio, Inc., Equator Therapeutics, Inc., Generian Pharmaceuticals, Fortress Biotech, Inc., OrsoBio, Aro Biotherapeutics Company, Stock/Shareholder; Levels Health, Inc.
1570-P: Myeloid-Specific Inactivation of Basp1 Protects Mice from Diet-Induced NASH through Attenuating NLRP3 Inflammasome Activation
Authors: MENG ZIYI , ZHOU LINKANG , HONG SUNGKI , LIU TONGYU , QIU XIAOXUE , CHEN ZHIMIN , LI SIMING , INOKI KEN , LIN JIANDIE
Published: June 2023

Nonalcoholic steatohepatitis (NASH) is characterized by persistent liver injury, inflammation, and fibrosis. Myeloid cells, including macrophages and dendritic cells, play an integral role in host defense, tissue homeostasis, and disease progression. Despite this, how myeloid cells contribute to NASH pathogenesis remains obscure. We previously identified NASH-associated macrophages (NAMs) as a unique population of monocyte-derived macrophages in NASH liver. We observed that hepatic NAMs exhibited abundant expression of Brain acid-soluble protein 1 (Basp1), which was markedly induced in the liver upon diet-induced NASH in mice. We generated myeloid-specific Basp1 knockout (Mye-Basp1 KO) mice to determine its role in NASH pathogenesis. Compared to control, Mye-Basp1 KO mice displayed significantly improved liver injury and fibrosis following NASH diet feeding, as shown by lower plasma ALT/AST levels and reduced Sirius Red staining on liver sections, respectively. Hepatocytes from Mye-Basp1 KO mice contained smaller lipid droplets without altering the total liver triglyceride content. Mechanistically, bone marrow-derived macrophages (BMDMs) lacking Basp1 exhibited diminished response to pro-inflammatory stimuli. Importantly, Basp1-deficient BMDMs displayed impaired activation of the NLRP3 inflammasome and secretion of interleukin-1 beta. Together, we propose that Basp1 is a novel regulator of inflammatory signaling in myeloid cells that plays a critical role in NASH pathogenesis.

Disclosure

Z.Meng: None. L.Zhou: None. S.Hong: None. T.Liu: None. X.Qiu: None. Z.Chen: None. S.Li: None. K.Inoki: None. J.Lin: None.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (DK102456)
1572-P: USP30 Regulates Hepatic Mitophagy and Mitochondrial Function
Authors: FAGUNLOYE OLAYEMI G. , BELLO FIONA , VANDEVENDER AMBER , SIPULA IAN J. , JURCZAK MICHAEL J.
Published: June 2023

Mitochondria regulate several cellular and metabolic processes, necessitating cells to employ highly evolved quality control mechanisms to remove damaged mitochondria through a selective form of autophagy called mitophagy. Mitophagy is a mitochondrial quality control pathway, mediated in part by the ubiquitination of outer mitochondrial membrane (OMM) proteins. USP30 is an OMM deubiquitinase that regulates mitophagy by degrading OMM ubiquitin, thus inhibiting mitophagy. Hepatic mitophagy is reduced in obese fatty liver and is associated with mitochondrial dysfunction. Whether USP30 regulates mitophagy in hepatocytes in vivo and affects mitochondrial function is currently unknown. Therefore, we utilized the Cre-lox system to modulate USP30 expression in vivo to determine the effects on hepatic mitochondrial and metabolic function. Tail-vain injection of AAV8-TBG-Cre into USP30fl/fl and wild-type C57BL6 male mice was used to generate liver-specific USP30 knockout (LKO) and control mice (WT). Mice were fed regular chow and sacrificed at 16 weeks of age, 6 weeks after AAV dosing. Mitochondrial respiratory capacity was assessed using purified liver mitochondria and lipid metabolism was assessed biochemically in mice liver and plasma. USP30 liver-specific deletion in mice resulted in an impaired mitochondrial respiratory capacity as evidenced by increased mitochondrial leak respiration and reduced ADP-stimulated respiration in LKO mice compared to WT, such that the respiratory control ratio was significantly reduced in LKO mice. There were no differences in liver triglyceride levels, nor plasma triglycerides or fatty acids, while plasma cholesterol levels were 25% reduced in LKO mice (p=0.051). These data demonstrate that USP30 is an important regulator of mitochondrial respiratory capacity in hepatocytes in vivo, and that USP30 may normally inhibit excessive non-selective mitophagy in otherwise healthy mice.

Disclosure

O.G.Fagunloye: None. F.Bello: None. A.Vandevender: None. I.J.Sipula: None. M.J.Jurczak: None.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (R01DK114012)
1577-P: Hepatic Steatosis and Glucose Intolerance in Liver-Specific Estrogen Receptor Alpha Knockout Mice
Authors: SUCUPIRA FELIPE , ARAUJO LAYANNE , PAULO CAMPOREZ JOAO
Published: June 2023

One of the consequences of sedentary lifestyle and consumption of a high-fat diet is Nonalcoholic Fatty Liver Disease (NAFLD), which affects approximately 30% of adults and up to 10% of children in developed countries. Interestingly, metabolic complications, such as insulin resistance and obesity, are less frequent in young women than in men of the same age or in postmenopausal women. In fact, reduced estrogen concentration during menopause is associated with increased visceral fat, metabolic diseases, insulin resistance, and T2DM. However, how estradiol is related to the development and progression of NAFLD remains unknown. Therefore, the general objective of this project was to study (in vivo) the effects of estrogen receptor alpha (ERα) ablation on hepatic energy metabolism. To this end, C57BL6 mice with ERα deletion specifically in the liver were generated using the Cre-Lox system (LERaKO). Sixth-week-old mice (Control and LERaKO mice) were fed a high-fat diet (HFD) with 45% fat. LERaKO mice displayed no difference in final body weight compared with control mice after four weeks of HFD feeding. A glucose tolerance test (GTT) was also performed after four weeks of HFD feeding. LERaKO mice displayed an increase in glucose intolerance by ~21% (P<0.05) compared with control mice, despite showing no difference in insulin secretion over the course of the GTT. Interestingly, we observed an increase in hepatic triglyceride (TAG) content by ~157% (P<0.05) in LERaKO mice compared with control mice and a decrease in plasma triglyceride concentration. We did not observe a significant difference in the expression of pro- and anti-inflammatory genes, but observed a significant increase in the expression of genes related to lipid synthesis and gluconeogenesis (P<0.05). Taken together, these data confirm the hypothesis that ERα plays a pivotal role in hepatic metabolism in mice, as liver-specific ERα ablation leads to glucose intolerance and hepatic steatosis.

Disclosure

F. Sucupira: None. L. Araujo: None. J. Camporez: None.

Funding

FAPESP (2021/02638-9)