Diet-induced Insulin Research Articles

COMBINED EFFECT OF HORSE GRAM AND FENUGREEK SEED POWDERS IN HIGH FAT-HIGH SUCROSE DIET-INDUCED PRE-DIABETES IN RATS

Objective: The objective of the study was to investigate the combined effect of horse gram (HG) and fenugreek (FG) seed powders in high fat-high sucrose (HFHS) diet-induced pre-diabetes in rats. Methods: Wistar rats (140–200 g) of either sex were randomly divided into four groups (n=6). Group 1, normal control, received normal pellet diet; Group 2, pre-diabetic control, received HFHS diet; Group 3, prophylactic group, received HFHS diet along with HG (200 mg/kg) and FG (200 mg/kg) combination; and Group 4, therapeutic group, received HFHS diet for 9 weeks followed by HG (200 mg/kg) and FG (200 mg/kg) combination for 28 days. Fasting blood glucose, lipid profiles, and OGTT were carried out on the 9th week in Group 1, Group 2, and Group 3, and at the end of the study in Group 1, Group 2, and Group 4. Results: Treatment with HFHS diet for 9 weeks has significantly increased fasting blood glucose and lipid profiles in the pre-diabetic group when compared to the normal control group indicating induction of pre-diabetes in the pre-diabetic group. In the prophylactic group, horse gram and fenugreek are given simultaneously with HFHS has significantly decreased fasting blood glucose, lipid profiles when compared to the pre-diabetic group. In the therapeutic group, treatment was given after induction of pre-diabetes for 28 days. In the therapeutic group, there was a significant decrease in fasting blood glucose, lipid profiles compared to the pre-diabetic group. Conclusion: HFHS diet-induced pre-diabetes or insulin resistance is an effective model to study and evaluate various new therapeutic modalities. The findings of the present study suggest that consumption of FG and HG as food supplements could reduce the risk of getting diabetes and progression of pre-diabetes to diabetes.

244-LB: GPR75 Ablation Protects against Diet-Induced Obesity, Inflammation, and Insulin Resistance

Obesity related conditions including atherosclerosis and type 2 diabetes mellitus (T2DM) have a profound effect on cardiovascular health and morbidity. Recent reports by Akbari et. al. indicate that truncated loss of function variants of the orphan G-protein coupled receptor, GPR75, are associated with 5.3 kg lower bodyweight and 54% lower odds of obesity in heterozygous individuals (Science, 2021) . Based on these findings, we hypothesized that whole body deletion of Gpr75 protects against diet-induced obesity (DIO) and the resulting insulin resistance. Wild-type and Gpr75 null mice were subjected to 14 weeks of regular chow or high-fat diet (HFD) feeding. Body weight, intraperitoneal glucose and insulin tolerance tests, and pro-inflammatory cytokine gene expressions were measured initially and at week 14. There were no significant differences in body weight, glucose homeostasis, and tumor necrosis factor alpha (TNF-α) expression between wild-type (WT) and Gpr75 -/- (KO) mice at baseline. However, WT mice obtained a diabetogenic phenotype after HFD-feeding while the KO counterparts were protected as indicated by reduced body weight, (45.32 ± 1.387 grams vs. 28.29 ± 1.47 grams) and increased sensitivity to insulin (blood glucose 30 min after insulin injection as percent change, -28.5 ± 4.41% vs. -50.68 ± 4.15%, p<0.0001) . This correlated with a 1.98-fold decrease in brown adipose tissue (BAT) and 2.31-fold decrease in subcutaneous adipose tissue (SAT) TNF-α mRNA expression in KO compared to WT mice. Furthermore, there was a 3.19-fold reduction in circulating chemokine ligand 5 (CCL5) in KO compared to WT mice. This data may provide a potential novel target for the control of obesity-driven disorders such as inflammation and insulin resistance. Disclosure S. Hossain: None. E. Dirice: None. Funding NIH123203

Roles of Transmembrane Protein 97 (TMEM97) in Adipose Tissue and Skeletal Muscle.

The combination of sarcopenia and obesity (sarcopenic obesity) is associated with the development of metabolic syndrome and cardiovascular events. The molecular pathways that develop sarcopenic obesity have studied intensively. Transmembrane protein 97 (TMEM97) is 176 amino acids conserved integral membrane protein with four transmembrane domains that is expressed in several types of cancer. Its physiological significance in adipose tissue and skeletal muscle has been unclear. We studied TMEM97-transgenic mice and mice lacking TMEM97, and our findings indicate that TMEM97 expression is regulated in adipose tissue and skeletal muscle from obesity. TMEM97 represses adipogenesis and promotes myogenesis in vitro. Fat-specific TMEM97 transgenic mice showed systemic insulin resistance. Mice overexpressing TMEM97 in skeletal muscle exhibited systemic insulin resistance. Mice lacking TMEM97 were protected against diet-induced obesity and insulin resistance. These phenotypes are associated with the effects of TMEM97 on inflammation genes in adipose tissue and skeletal muscle. Our findings indicates that there is a link between TMEM97 and chronic inflammation in obesity.

1381-P: GDF15 Deficiency in Brown Adipose Tissue Does Not Affect Thermogenesis, but Exacerbates Diet-Induced Obesity

Growth and differentiation factor 15 (GDF15) is induced in brown adipocytes in response to thermogenic stimuli, as well as high-fat feeding in mice. However, whether brown adipose tissue (BAT) -derived GDF15 is required to regulate BAT thermogenesis or energy homeostasis is unclear. In the present study, we sought to test the hypothesis that BAT-derived GDF15 is necessary to mediate thermogenesis and systemic adaptations to diet-induced obesity (DIO) . We generated mice lacking GDF15 specifically in BAT by crossing Gdf15 floxed mice with mice harboring the Cre recombinase under the control of the Ucp1 promoter (GDF15 BAT KO) . GDF15 BAT KO mice were treated with the beta adrenoreceptor agonist CL316,243 (CL) for 5 days to induce thermogenesis, or fed a high-fat diet (60% fat content) for 12 weeks to induce DIO. CL treatment promoted a significant induction in Gdf15 mRNA levels in the BAT of WT mice, which, as expected, was prevented in KO mice. Nonetheless, serum GDF15 levels were similarly induced by CL in both WT and KO mice. CL-induced activation of thermogenic genes in BAT, such as Ucp1 and Dio2, was comparable between genotypes, and core body temperature was unchanged between WT and KO mice. After 12 weeks of high-fat feeding, KO mice had significantly increased body weight and fat mass relative to WT mice. However, food intake, locomotor activity and energy expenditure were unchanged between groups. Respiratory exchange ratio was significantly higher in KO mice, indicating a relative preference for carbohydrate as fuel. Although glucose tolerance was unchanged between genotypes, insulin sensitivity was impaired in KO mice. Taken together, our data indicates that BAT-derived GDF15 does not contribute to GDF15 circulating levels in response to CL treatment and is largely dispensable for CL-induced BAT thermogenesis. However, BAT-derived GDF15 seems to be required to regulate diet-induced weight gain and insulin sensitivity. Disclosure J.Jena: None. K.Kato: None. A.A.Marti: None. R.Pereira: None. Funding NIHDK125405

Abstract TP252: Intranasal Insulin Treatment Improves Stroke Outcome In Both Male And Female Mice

Insulin resistance has been linked to increased risk of stroke recurrence, death, and poor outcome following stroke. Insulin resistance, a common phenomenon following stroke, is associated with elevated levels of insulin circulating in the periphery, which leads to brain insulin deficiency. Brain insulin promotes neuroplasticity and synaptogenesis, has anti-inflammatory, anti-thrombotic, vasodilatory, and anti-apoptotic properties. The impact of brain insulin deficiency and the therapeutic potential of increasing brain insulin levels has yet to be fully understood. Hence, purpose of this study is to assess the potential therapeutic benefits of intranasal insulin treatment on stroke outcomes in a mouse model of brain insulin deficiency. Ischemic stroke was induced using a 30 minute middle cerebral artery occlusion (MCAO) in 16 week old (12 week diet) male and female mice on either a standard diet (control) or a high-fat diet induced at 4 weeks of age, a model of brain insulin deficiency. Recovery assessments begin on day 0 following stroke and continue until day 14 post stroke. Recovery assessments entail observing survival, neurological, motor, and cognitive function after receiving either intranasal saline (0.9%) or intranasal insulin (1.75 U). These assessments were evaluated by survival, and completion of the neurological severity score, ladder, and problem solving tasks on days 0-14 post stroke. High-fat diet-induced brain insulin deficiency was associated with worse survival and neurological deficits following ischemic stroke, intranasal insulin improved stroke mortality and neurological assessments in high-fat diet mice. Thus, intranasal insulin may be a useful therapy for improving stroke outcomes.

WW domain-binding protein 2 overexpression prevents diet-induced liver steatosis and insulin resistance through AMPK\u03b21

Nonalcoholic fatty liver disease (NAFLD) is prevalent clinically and can lead to more serious chronic liver disease. However, the pathological mechanism is still unclear, and thus, there are no approved drugs on the market. Transcriptional coactivator WW domain-binding protein 2 (WBP2) is a newly discovered oncogene that has an important relationship with the occurrence and development of breast cancer and mediates the interaction between Wnt and various other signaling pathways. The expression level of WBP2 was decreased in NAFLD. Overexpression of WBP2 with AAV in vivo alleviated liver fat deposition and insulin resistance induced by a high-fat diet (HFD). Knockdown of WBP2 with AAV aggravated HFD-induced fatty liver and insulin resistance. In vitro experiments showed that in the human normal hepatocyte cell line LO2 and primary hepatocytes isolated from mice, overexpression of WBP2 reduced fat deposition, and knocking out or knocking down WBP2 aggravated PA-induced fat deposition. Through mass spectrometry, we found that WBP2 can bind to AMPKβ1, and by mutating AMPKβ1, we found that WBP2 can induce phosphorylation of AMPKβ1 at S108 and then activate the AMPK pathway to affect lipid metabolism. The effect of WBP2 on NAFLD provides a possible new direction for future research on NAFLD.

Positive association between dietary acid load and future insulin resistance risk: findings from the Korean Genome and Epidemiology Study

BackgroundAcid-base homeostasis is increasingly being recognized to play an important role in normal metabolic function. However, prospective studies on the relationship between diet-induced acid-base imbalance and insulin resistance among Asian populations have been limited. Thus, we investigated whether diet-induced metabolic acidosis was prospectively associated with insulin resistance risk in middle-aged and older Korean adults.MethodsIn total, 5406 participants from the Korean Genome and Epidemiology Study without type 2 diabetes, insulin resistance, cancer, or renal diseases at baseline examination were included in this study. To estimate diet-induced metabolic acidosis, we used potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores calculated from the usual dietary intake assessed by a validated 103-item food frequency questionnaire at baseline. Multivariable Cox proportional hazard models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of insulin resistance incidence.ResultsDuring a mean follow-up period of 7.4 years, we documented 3449 insulin resistance cases. In the fully adjusted model, the future insulin resistance risk was significantly higher among participants in the highest quartiles of PRAL (HR: 1.30, 95% CI: 1.13–1.48, Ptrend = 0.0002) and NEAP (HR: 1.30, 95% CI: 1.14–1.49, Ptrend = 0.0008) than among those in the lowest quartiles. Associations were slightly strengthened among men, adults < 50 years old, obese participants, or those with low physical activity levels.ConclusionsOur findings suggested that diet-dependent acid load was positively associated with the future development of insulin resistance, suggesting effect modification by sex, age, the presence of obesity, and physical activity levels.

MiR-125b-2 knockout increases high-fat diet-induced fat accumulation and insulin resistance

Obese individuals are more susceptible to comorbidities than individuals of healthy weight, including cardiovascular disease and metabolic disorders. MicroRNAs are a class of small and noncoding RNAs that are implicated in the regulation of chronic human diseases. We previously reported that miR-125b plays a critical role in adipogenesis in vitro. However, the involvement of miR-125b-2 in fat metabolism in vivo remains unknown. In the present study, miR-125b-2 knockout mice were generated using CRISPR/CAS9 technology, resulting in mice with a 7 bp deletion in the seed sequence of miR-125b-2. MiR-125b-2 knockout increased the weight of liver tissue, epididymal white fat and inguinal white fat. MiR-125b-2 knockout also increased adipocyte volume in HFD-induced obese mice, while there were no significant differences in body weight and feed intake versus mice fed a normal diet. Additionally, qRT-PCR and western blot analysis revealed that the expression of the miR-125b-2 target gene SCD-1 and fat synthesis-associated genes, such as PPARγ and C/EBPα, were significantly up-regulated in miR-125b-2KO mice (P < 0.05). Moreover, miR-125b-2KO altered HFD-induced changes in glucose tolerance and insulin resistance. In conclusion, we show that miR-125b-2 is a novel potential target for regulating fat accumulation, and also a candidate target to develop novel treatment strategies for obesity and diabetes.

Myeloid FBW7 deficiency disrupts redox homeostasis and aggravates dietary-induced insulin resistance

The E3 ubiquitin ligase FBW7 plays critical roles in multiple pathological and physiological processes. Here, we report that after high-fat diet (HFD) feeding for 16 weeks, myeloid-specific FBW7-deficient mice demonstrate increased redox stress, inflammatory responses and insulin resistance. Macrophages activation under FBW7 deficiency decreases substrate flux through the pentose phosphate pathway (PPP) to produce less equivalents (NADPH and GSH) and aggravate the generation of intracellular reactive oxygen species (ROS) in macrophages, thereby over-activating proinflammatory reaction. Mechanistically, we identify that pyruvate kinase muscle isozyme M2 (PKM2) is a new bona fide ubiquitin substrate of SCFFBW7. While challenged with HFD stress, pharmacological inhibition of PKM2 protects FBW7-deficient macrophages against production of ROS, proinflammatory reaction and insulin resistance. Intriguingly, we further find an inverse correlation between FBW7 level and relative higher H2O2 level and the severity of obesity-related diabetes. Overall, the results suggest that FBW7 can play a crucial role in modulating inflammatory response through maintaining the intracellular redox homeostasis during HFD insults.

Abstract MP121: Deleting the 2-oxoglutarate- and Iron-dependent Prolyl Hydroxylase Ogfod1 Alters Purine Nucleotide Regulation and is Cardioprotective

Prolyl hydroxylation is a post-translational modification that regulates protein stability, turnover, and activity. The proteins that catalyze prolyl hydroxylation belong to the 2-oxoglutarate- and iron-dependent oxygenase family of enzymes. A newly-described member of this family is 2-oxoglutarate- and iron-dependent oxygenase domain containing protein 1 (Ogfod1), which catalyzes prolyl hydroxylation of the ribosomal protein s23 (Rps23). To investigate the cardiovascular function of Ogfod1, we isolated hearts from 5 Ogfod1 -WT and 5 Ogfod1 -KO mice and used Liquid Chromatography and Tandem Mass Spectrometry (LC-MS/MS) to identify proteomic changes. Ingenuity Pathway Analysis (IPA) identified “Purine Nucleotides Degradation II (Aerobic)” ( P = 0.00017) to be one of the most significantly-enriched pathways. We then did metabolomics and found that Inosine 5’-monophosphate (IMP) was 3.5x higher in Ogfod1 -KO hearts ( P = 0.011), further supporting a role for Ogfod1 in regulating purine nucleotide metabolism. Recent evidence has shown that altering purine nucleotide degradation protects against diet-induced obesity and insulin resistance, so we tested this hypothesis in Ogfod1 -KO mice by feeding them high-fat diets. Ogfod1 ablation protects against high-fat diet-induced obesity and insulin resistance. Altering purine nucleotide degradation has also been shown to be protective against cardiac injury, so we tested the hypothesis that Ogfod1 loss protects the heart from ischemia-reperfusion (I/R) injury by subjecting perfused hearts from 6 Ogfod1 -WT and 6 Ogfod1 -KO mice to ischemia and reperfusion and assessed tissue death. We found a 37% decrease in infarct size in Ogfod1 -KO hearts (56% in Ogfod1 -WT and 35% in Ogfod1 -KO, P = 0.0003). In a separate set of experiments, we treated Ogofd1 -KO mice with isoproterenol to induce hypertrophy, and Ogfod1 -KO hearts showed protection against hypertrophic remodeling. Interestingly, OGFOD1 transcripts were up-regulated in human heart failure, indicating a potential role for OGFOD1 in the human failing heart. Altogether, these data show that Ogfod1 deletion alters the myocardial proteome and myocardial metabolism and protects against obesity, insulin sensitivity, I/R injury, and hypertrophy.

Integrated analysis of differentially expressed long noncoding RNAs and mRNAs associated with high-fat diet-induced hepatic insulin resistance in mice

BackgroundHepatic insulin resistance (IR) is an early pathological characteristic of many metabolic diseases, such as type 2 diabetes. Long noncoding RNAs (lncRNAs) have been identified as mediators of IR and related diseases. However, the roles of lncRNAs in hepatic IR remain largely unknown.MethodHigh-throughput sequencing was performed on ten liver tissue samples from five normal diet (ND)-fed mice and five high-fat diet (HFD)-induced hepatic IR mice, respectively. lncRNAs and mRNAs that were differentially expressed (DE) between the two groups were identified by bioinformatic analyses. Seven DE lncRNAs were validated by quantitative real-time PCR (q-PCR). The potential functions of the DE lncRNAs were predicted by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of target genes. In addition, integrated analysis was performed for the DE lncRNAs and mRNAs to predict their interaction relationships.ResultsA total of 232 DE lncRNAs were identified in the HFD-induced hepatic IR mice compared with the ND-fed mice. These DE lncRNAs included 108 upregulated and 124 downregulated lncRNAs, and 7 of the DE lncRNAs were validated by q-PCR. In addition, 291 DE mRNAs including 166 upregulated and 125 downregulated mRNAs were identified in the HFD group. Furthermore, target genes of the DE lncRNAs were predicted, and functional enrichment results showed that the enriched genes were involved in IR- and glycolipid metabolism-related processes. Additionally, the coexpression network was also constructed to further reflect the potential functions of the DE lncRNAs.ConclusionThe study describes the expression profiles of lncRNAs and mRNAs and the functional networks involved in HFD-induced hepatic IR. These findings may provide a new perspective for the study of lncRNAs in hepatic IR- and glycolipid metabolism-related diseases.

1727-P: Mice Deficient in Myeloid Cell-Derived Interleukin-1a Are Protected from Diet-Induced Obesity and Insulin Resistance

Interleukin (IL)-1α is a major mediator of inflammation, and functional polymorphism of IL-1α is associated with human obesity. We have recently generated mice with genetic ablation of IL-1α selectively in myeloid cells. On chow diet, Lyz-IL-1α KO mice showed normal metabolic phenotypes. In contrast, when male Lyz-IL-1α KO mice were fed a high-fat diet (HFD), whole body fat mass was markedly reduced in these mice (Figure 1; *P&amp;lt;0.05). Metabolic cage study found that this was mostly due to a 2-fold increase in physical activity in Lyz-IL-1α KO mice (Figure 2). Food intake and energy expenditure were not affected in these mice. We performed a hyperinsulinemic-euglycemic clamp to measure insulin sensitivity in awake mice (n=7). HFD-fed Lyz-IL-1α KO mice were more insulin sensitive than HFD-fed wild type (WT) mice with a 2-fold increase in glucose infusion rates (Figure 3). Whole body glucose turnover and glycolysis were significantly increased in HFD-fed Lyz-IL-1α KO mice (Figure 3). Basal hepatic glucose production (HGP) was not altered, but clamp HGP was reduced by 40% in Lyz-IL-1α KO mice. As a result, hepatic insulin action was markedly increased in HFD-fed Lyz-IL-1α KO mice (Figure 4). In conclusion, these results indicate that Lyz-IL-1α KO mice are protected from diet-induced obesity and insulin resistance, and our findings identify IL-1α as a novel therapeutic target in obesity and type 2 diabetes. Disclosure S. Suk: None. R.H. Friedline: None. H. Noh: None. X. Hu: None. D.A. Tran: None. L.A. Tauer: None. A.M. Kim: None. L.H. Kim: None. J.K. Kim: None. Funding National Institutes of Health (5U2CDK093000)

372-OR: Ablation of the Hepatokine TSK Protects Mice against Obesity and Metabolic Disorders Caused by MC4R Deficiency

Endocrine hormones released by peripheral tissues, such as adipose tissue, skeletal muscle and the liver, play an important role in metabolic crosstalk and homeostasis and contribute to disease pathogenesis. We recently identified Tsukushi (TSK) as a liver-enriched secreted factor that is highly inducible in response to increased energy expenditure. TSK null mice were resistant to diet-induced obesity, insulin resistance, and diet-induced NASH as a result of enhanced sympathetic activation and brown fat thermogenesis. However, the mechanisms underlying TSK action remain incompletely elucidated. Melanocortin 4 receptor (MC4R) is a key regulator of energy balance and its mutations represent the most common monogenic cause of obesity in human. In this study, we generated TSK/MC4R double knockout mice to explore potential crosstalk between the TSK and MC4R signaling pathways. While MC4R-null mice developed severe obesity when fed standard rodent chow, TSK inactivation nearly completely abolished the defects of energy balance caused by MC4R deficiency. Remarkably, ablation of TSK normalized food intake and corrected hepatic steatosis, adipose tissue inflammation, and insulin resistance in MC4R null mice. TSK deficiency also rescued the impairments of thermogenic gene expression caused by MC4R deficiency. Those results suggest that TSK likely acts downstream or in parallel to MC4R signaling to regulate feeding behavior and energy expenditure. Our work supports a rationale for therapeutic blockade of TSK for the treatment of obesity and metabolic disease caused by MC4R mutations. Disclosure Q. Wang: None. J. Lin: None. Funding National Institutes of Health (DK102456, AG055379, DK114220)

1808-P: Hepatocyte Traf Family Members Link Inflammation to Liver Steatosis and Insulin Resistance

Obesity is associated with chronic inflammation that exacerbates insulin resistance and metabolic disease. Inflammation drives the pathogenesis of nonalcoholic fatty liver disease (NAFLD), hepatic manifestations of obesity. Hepatic inflammatory microenvironments are believed to induce reprogramming of metabolic pathways; however, intracellular molecules coupling inflammation to metabolism remain poorly understood. Cytokines, damage-associated (DAMPs) and pathogen-associated molecular patterns (PAMPs) are known to activate Traf family members that in turn activate the NF-κB and other inflammatory pathways. We previously reported that hepatic Traf2 and Traf3 augment hepatic glucose production. Here, we demonstrate that hepatocyte Traf2, Traf3 and Traf6 act in concert to promote liver steatosis and insulin resistance. We ablated hepatocyte Traf2, Traf3, and Traf6 individually and in combination (Traf2,3,6Δhep) in adult Traf2flox/flox, Traf3flox/flox, Traf6flox/flox, and Traf2,3,6flox/flox mice, respectively, using AAV-TBG-Cre vectors. Metabolic abnormality was more severe in Traf2,3,6Δhep mice relative to Traf2Δhep, Traf3Δhep and Traf6Δhep mice. Remarkably, Traf2,3,6Δhep mice were resistant to high fat diet-induced liver steatosis, insulin resistance, and glucose intolerance. Hepatic PPARα, a master regulator of fatty acid β oxidation, was substantially elevated in Traf2,3,6Δhep mice. Conversely, in primary hepatocytes, overexpression of Traf3 markedly decreased PPARα stability and protein levels. Traf3 coimmunoprecipitated with PPARα and decreased PPARα transcriptional activity. In primary hepatocytes, ablation of Traf2, Traf3 and Traf6 significantly increased fatty acid β oxidation, and overexpression of Traf3 had the opposite effects. Together, our results unveil an unrecognized hepatocyte Traf/PPARα/fatty acid β oxidation pathway that couples inflammation to liver steatosis and insulin resistance in obesity. Disclosure Z. Zhang: None. H. Lin: None. X. Zhong: None. L. Rui: None.

1960-P: A Novel Nitric Oxide Releasing Nanomatrix Gel Prevents High-Fat Diet-Induced Obesity and Insulin Resistance

Endothelial dysfunction is characterized by reduction of the bioavailability of nitric oxide (NO), and is associated with metabolic syndrome including, obesity, insulin resistance, hypertension, coronary heart disease, and aging. Because NO plays important roles in mitochondrial biogenesis, we hypothesize that exogenous application of NO may prevent high fat diet (HFD)-induced obesity and insulin resistance by promotion of adipose tissue browning. In the current study, we developed a novel NO releasing nanomatrix gel with natural peptide amphiphiles (PANO). 8 week old male C57BL/6 mice were randomly divided into 2 groups, and then either vehicle (PA) or PANO was subcutaneously injected into brown adipose tissue area every 2 weeks for 11 weeks while the mice were fed HFD. The mice injected with PANO gained less body weight compared to the mice injected with vehicle. PANO injected mice demonstrated improved glucose tolerance and insulin tolerance. Fasting glucose, insulin and leptin levels were lower in the PANO injected mice compared to the vehicle injected mice. Furthermore, the expression of pro-inflammatory genes in epididymal fat tissue was lower, and the expression of uncoupled protein (UCP1) in brown adipose tissue and inguinal adipose tissue was higher in the PANO-injected mice compared to the vehicle injected mice. Thus, the novel nitric oxide releasing nanomatrix gel ameliorated HFD-induced obesity and insulin resistance by promotion of adipose tissue browning. The results suggest that injection of PANO can be a novel therapeutic for obesity and insulin resistance. Disclosure G. Ren: None. A.L. Shaw: None. P. Hwang: None. R.C. Millican: None. H. Jun: None. J. Kim: None. Funding National Institutes of Health (1R01HL125391-01)

1654-P: Deletion of the Mammalian Indy Homolog (Slc13a5) Improves Hepatic Insulin Sensitivity through Vagal Nerve Signaling

Background: INDY (I’m Not Dead Yet) is a plasma membrane citrate transporter and is highly expressed in liver and brain. In mammals, whole body deletion of the coding gene (mIndy, Slc13a5) increased energy expenditure and protected mice from diet-induced obesity and insulin resistance. Generation of neuronal mIndy-KO (NINKO) mice revealed improved insulin sensitivity (IS) in these mice, mediated through better hepatic IS. Gene expression studies in wildtype C57Bl/6 mice revealed high expression of mIndy in the hypothalamus (HTM), which is the main brain area regulating hepatic glucose metabolism. One mechanisms is the regulation through AMPK. Reduced hypothalamic AMPK phosphorylation is known to reduce hepatic glucose output, probably mediated via vagal nerve signaling. Hypothesis: Hepatic glucose production is regulated via mIndy expression in the HTM. Methods: Hyperinsulinemic-euglycemic clamp studies were performed to assess IS after hepatic vagotomy of NINKO mice. NestinCre+ controls were sham-denervated. Ex vivo brain slices of C57Bl/6 mice and the neuronal hypothalamic cell line CLU183 were acutely stimulated with 1 mM sodium citrate to investigate the effect of citrate on the brain and neurons. Results: Acute stimulation of brain slices and CLU183 cells with citrate decreased cellular respiration (-19.7%, p≤0.01), ATP production (-37.7%, p≤0.01) and increased AMPK phosphorylation (+24.7%, p≤0.001). In line with that, AMPK phosphorylation in the HTM of NINKO mice was significantly reduced (-68.1%, p≤0.05). With hepatic branch vagotomy, no differences in hepatic IS could be observed anymore (suppression of basal hepatic glucose output (%); NestinCre+: 100.0±27.2, NINKO: 99.4±8.8). Conclusion: These data suggest that neuronal mIndy is a critical regulator of glucose homeostasis in mammals, probably regulated via AMPK phosphorylation in the HTM and vagal nerve signaling. Further studies will address the exact mechanisms involved in the effect. Disclosure A. Kurzbach: None. M. Schell: None. D.M. Willmes: None. N. El-Agroudy: None. A. Kleinridders: None. A.L. Birkenfeld: None.

P0997BLUEBERRY JUICE IMPROVED THE METABOLIC PROFILE IN A PREDIABETIC RAT MODEL INDUCED BY A HYPERCALORIC DIET WITHOUT RENOPROTECTION

Abstract Background and Aims Blueberries (BB), due to their enriched content in polyphenolics and in other compounds with potential cytoprotective properties, have been associated with beneficial effects in distinct cardiometabolic conditions. The goal of this study was to evaluate the metabolic and renal effects of long-term blueberry juice (BJ) treatment in a rat model of prediabetes induced by a hypercaloric diet. Method Prediabetes was developed in adult male Wistar rats through the ingestion of high-sucrose (35% HSu) and high-fat (60% HF) diets during 23 wks (HSuHF animals, n=16). After 9 weeks, half of the former rats received BJ orally (25g/kg BW, HSuHF+BJ group). Control animals (n=8) received standard diet during the entire protocol. Glycemic, lipidic and insulinemic profiles were evaluated throughout the protocol, as well as gut microbiota composition, gut barrier permeability, endotoxemia (LPS) and inflammation (hs-CRP). Renal function was assessed by using serum and urinary measures of creatinine, uric acid and blood urea nitrogen and calculating the glomerular filtration rate (GFR). Histological characterization of the kidney was performed by H&amp;E and lipid deposition by Oil Red O staining and quantification of triglycerides. Serum and renal tissue inflammatory markers were evaluated by Elisa (hs-CRP) and by RT-qPCR and/or WB (IL-6, TNF-α, iNOS, MMP2, TLR-4 and RAGE). The study was approved by the local animal welfare body (Ref: 9-2018). Values are presented as means ± S.E.M. and possible differences evaluated by ANOVA/post-hoc tests. Results While no major changes between groups were found for gut microbiota, gut barrier and endotoxemia/inflammation, BJ treatment was able to ameliorate hypercaloric diet-induced glucose intolerance, insulin insensitivity and plasma hypertriglyceridemia. In addition, in the HSuHF+BJ rats there was a trend to alleviate the reduction of GFR found in the HSuHF animals, as well as some early glomerular lesions, including mesangial expansion and basal membrane thickening. However, this nutraceutical intervention was unable to halt or slow down glomerular crescent-like lesions, renal lipidosis and the overexpression of renal IL-6 found in the HSuHF-treated animals. Conclusion Despite the metabolic improvement viewed by the amelioration of glucose intolerance, insulin insensitivity and hypertriglyceridemia, in this rat model of prediabetes a nutraceutical intervention with BJ presented very modest renoprotective effects. Acknowledgements: FEDER, COMPETE and FCT (CENTRO-01-0145-FEDER-000012-HealthyAging2020, UID/NEU/04539/2013, UID/NEU/04539/2019, POCI-01-0145-FEDER-007440, POCI-01-0145-FEDER-031712, PTDC/SAU-NUT/31712/2017 and SFRH/BD/109017/2015), as well as COAPE and MIRTILUSA.

1964-P: Slug Epigenetically Represses Adipose Thermogenic Programs

Thermogenic fat, such as brown adipose tissue (BAT) and beige fat, gains increasing attention due to its ability to protect against obesity and type 2 diabetes. Brown adipocytes and beige adipocytes contain dense mitochondria that burn glucose and free fatty acids to produce heat, and mitochondrial Ucp1 mediates heat production. Coactivator PGC1α is a master regulator of mitochondrial biogenesis and Ucp1 expression, and profoundly influences the energy expenditure capability of thermogenic fat. We attempted to delineate transcriptional regulators that govern thermogenic fat activity through PGC1α, and identified transcriptional repressor Slug. Both human and mouse PGC1α promoters contain multiple Slug binding motifs. Slug potently suppressed the activity of PGC1α promoter luciferase reporters but not mutant PGC1α promoters lacking Slug motifs. Consistently, Slug physically bound to the PGC1α promoter and decreased the levels of PGC1α promoter H3K9 acetylation, a transcriptionally-active epigenetic mark, presumably by recruiting HDAC1/2 to the promoter. In line with this notion, treatment with HDAC1/2 inhibitor trichostatin A abrogated the ability of Slug to suppress PGC1α promoter luciferase reporters. Remarkably, deletion of Slug substantially increased expression of PGC1α and Ucp1 in both BAT and inguinal fat in mice, and increased H3K9 acetylation levels on the PGC1α promoter in BAT. Slug-deficient BAT had increased O2 consumption rates and thermogenesis capability. Slug knockout mice were resistant to high fat diet-induced obesity, insulin resistance, glucose intolerance, and fatty liver disease. Likewise, adipocyte-specific deletion of Slug also ameliorated HFD-induced glucose intolerance. Unlike global Slug knockout mice, adipocyte-specific Slug knockout mice displayed mild metabolic phenotypes. In conclusion, our data suggest that Slug regulates thermogenic fat energy expenditure at least in part by epigenetically suppressing the PGCα-mitochondria axis. Disclosure Q. Kang: None. L. Jiang: None. L. Rui: None.

Acute emotional stress and high fat/high fructose diet modulate brain oxidative damage through NrF2 and uric acid in rats

Studies focusing on the interaction of dietary and acute emotional stress on oxidative stress in cortex frontal and in brain mitochondria are scarce. Dietary-induced insulin resistance, as observed in Western diets, has been associated with increased oxidative stress causing mitochondrial dysfunction. We hypothesized that acute emotional stress could be an aggravating factor by impacting redox status in cortex and brain mitochondria. Thus, the aim of the present study was to evaluate the combination of an insulin resistance inducing high-fat/high-fructose (HF/HFr) diet and acute emotional stress on brain oxidative stress in rats. We measured several oxidative stress parameters (carbonyls, FRAP, TBARS assays, GSH, GSSG, oxidized DNA, mRNA expression of redox proteins (Nrf2), and uric acid). The HF/HFr diet resulted in increased oxidative stress both in the brain mitochondria and in the frontal cortex and decreased expression of the Nrf2 gene. The emotional stress induced an oxidative response in plasma and in brain mitochondria of the control group. In the HF/HFr group it triggered an increase expression of the redox transcription factor Nrf2 and its downstream antioxidant genes. This suggests an improvement of the redox stress tolerance in response to an enhanced production of reactive oxygen species. Accordingly, a blunted oxidative effect on several markers was observed in plasma and brain of HF/HFr-stressed group. This was confirmed in a parallel study using lipopolysaccharide as a stress model. Beside the Nrf2 increase, the stress induced a stronger UA release in HF/HFr which could take a part in the redox stress.

Improvement in High-fat Diet-induced Obesity and Insulin Resistance upon Uptake of PS-B1, a Fermented Product Prepared from Soy Flour Using Lactic Acid Bacteria

PS-B1 is a fermented product prepared from soy flour using lactic acid bacteria. Over a 10-week period, C57BL/6J mice were reared under laboratory conditions on a normal diet (control, n=5), high-fat diet (HF, n=5), or high-fat diet supplemented with 4% PS-B1 (HF-P, n=6). After 10 weeks, the change in weight gain, intestinal and epididymal fat accumulation, serum and liver biochemical parameters, and gene expression in the mice was investigated. HF diet-induced weight gain and increase in intestinal and epididymal fat accumulation were lower in mice fed with HF-P diet than in mice fed with HF diet, suggesting that PS-B1 prevented HF diet-induced obesity in HF-P mice. Furthermore, the levels of liver lipids (triglycerides, TG; non-esterified fatty acid, NEFA; total cholesterol, TC), serum TC, serum glucose, and serum insulin were significantly increased in the HF group than those in control mice. In HF-P mice, neither serum TC nor serum glucose levels were reduced. In contrast, the levels of liver lipids and serum insulin were lower in HF-P mice than in HF mice, suggesting that PS-B1 reduced these parameters in HF-P mice. The homeostatic model assessment of insulin resistance (HOMA-IR) value, which was calculated from the serum glucose and insulin levels, was 21.5 ± 4.2 in the HF mice. However, the HOMA-IR (8.2 ± 0.2) values were significantly decreased in the HF-P mice, suggesting that PS-B1 improves insulin resistance. Additionally, we compared the expression levels of stearoyl-CoA desaturase-1 (Scd1) in the liver. Quantitative RT-PCR showed increased expression of Scd1 in HF mice compared to that in control mice. Furthermore, ingestion of PS-B1 led to reduced expression of Scd1 mRNA in HF-P mice, implying that PS-B1 is effective in reducing the expression of the gene encoding SCD1. These results suggest that the anti-obesity effect of PS-B1 and improvement in fat accumulation upon PS-B1 uptake may be due to improvement in insulin resistance and reduction in the expression level of Scd1.