Abstract 330: Glycogen Synthase Kinase-3a Negatively Regulates Fatty Acid Metabolism During Lipid-induced Insulin Resistance

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Michinari Nakamura ◽  
Junichi Sadoshima
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Metabolism ◽  
Lipid Accumulation ◽  
Acid Metabolism ◽  
Glycogen Synthase ◽  
Acid Oxidation ◽  
Peroxisome Proliferator

Obesity and insulin resistance lead to ectopic lipid accumulation and impaired cardiac metabolism, resulting in cardiovascular diseases. Peroxisome proliferator-activated receptor α (PPARα) is highly expressed in the heart and serves as a key regulator of fatty acid metabolism. However, the underlying mechanisms responsible for the development of cardiac dysfunction in these pathologies are still poorly understood. GSK-3α was activated, as evidenced by a decrease in S21 phosphorylation, during insulin resistance with normoglycemia in the hearts of obese mice fed a high-fat diet and ob/ob mice. To evaluate the functional significance of GSK-3α upregulation with regard to metabolism, we applied 50 μM of BSA-conjugated palmitic acid to cardiomyocytes in vitro for three days. This intervention elicited ectopic lipid accumulation, as evaluated with Oil Red O staining, and a 2.0-fold activation of GSK-3α, similar to lipid-induced insulin resistance and dyslipidemia in the heart in vivo . In this condition, downregulation of GSK-3α with shRNA-GSK-3α in cardiomyocytes increased cell viability, ATP synthesis, and fatty acid oxidation, but not glycolysis. Downregulation of GSK-3α also increased the activity of PPRE-luciferase (1.5 fold, p<0.05) and mRNA expression of genes involved in fatty acid metabolism in response to palmitic acid, including Acox1 and Cpt1b . Overexpression of GSK-3α induced a rightward shift of the dose response curve where the activity of the PPARα reporter was plotted against the dose of WY14643, a PPARα agonist. GSK-3α, but not GSK-3β, directly interacted with and phosphorylated PPARα in vitro . Collectively, these results suggest that GSK-3α negatively regulates ligand-dependent activity of PPARα through phosphorylation of PPARα, thereby inhibiting fatty acid metabolism during lipid-induced insulin resistance. GSK-3α may be a novel therapeutic target for metabolic disorders.

scholarly journals Effects of Dietary Anaplerotic and Ketogenic Energy Sources on Renal Fatty Acid Oxidation Induced by Clofibrate in Suckling Neonatal Pigs

2020 ◽  
Vol 21 (3) ◽  
pp. 726
Author(s):  
Xi Lin ◽  
Brandon Pike ◽  
Jinan Zhao ◽  
Yu Fan ◽  
Yongwen Zhu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Energy Sources ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Fresh Tissue ◽  
Peroxisome Proliferator Activated Receptor ◽  
Tissue Homogenates

Maintaining an active fatty acid metabolism is important for renal growth, development, and health. We evaluated the effects of anaplerotic and ketogenic energy sources on fatty acid oxidation during stimulation with clofibrate, a pharmacologic peroxisome proliferator-activated receptor α (PPARα) agonist. Suckling newborn pigs (n = 72) were assigned into 8 dietary treatments following a 2 × 4 factorial design: ± clofibrate (0.35%) and diets containing 5% of either (1) glycerol-succinate (GlySuc), (2) tri-valerate (TriC5), (3) tri-hexanoate (TriC6), or (4) tri-2-methylpentanoate (Tri2MPA). Pigs were housed individually and fed the iso-caloric milk replacer diets for 5 d. Renal fatty acid oxidation was measured in vitro in fresh tissue homogenates using [1-14C]-labeled palmitic acid. The oxidation was 30% greater in pig received clofibrate and 25% greater (p < 0.05) in pigs fed the TriC6 diet compared to those fed diets with GlySuc, TriC5, and Tri2MPA. Addition of carnitine also stimulated the oxidation by twofold (p < 0.05). The effects of TriC6 and carnitine on palmitic acid oxidation were not altered by clofibrate stimulation. However, renal fatty acid composition was altered by clofibrate and Tri2MPA. In conclusion, modification of anaplerosis or ketogenesis via dietary substrates had no influence on in vitro renal palmitic acid oxidation induced by PPARα activation.

Fatty acid metabolism in segments of rat intestine

1965 ◽  
Vol 208 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Daniel Porte ◽  
Cecil Entenman
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Sodium Taurocholate ◽  
Tissue Uptake ◽  
Rat Intestine ◽  
A Minor

The in vitro metabolism of albumin-bound palmitic acid-1-C14 by segments of small intestine was studied. Tissue uptake, esterification, and oxidation of the fatty acid were measured separately and found to respond independently to altered incubation conditions. Uptake was reversible, and did not require glucose or oxygen. It was not inhibited by fluoride or arsenate. Esterification required both glucose and oxygen, but was unaffected by insulin. It was depressed by succinate and almost completely inhibited by fluoride and arsenate. Oxidation was a minor fate for fatty acid. It was independent of glucose but inhibited by succinate, fluoride, and arsenate. Sodium taurocholate stimulated uptake, but not esterification, as has been previously reported. The possible significance of the reversible tissue uptake reaction is discussed.

scholarly journals Maternal Feeding of a Synthetic PPARα Agonist Alters Renal Development of Fatty Acid Metabolism in the Neonatal Piglet

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 702-702
Author(s):  
Lin Xi ◽  
Brandon Pike ◽  
Jinan Zhao ◽  
Jack Odle
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Block Design ◽  
Energy Utilization ◽  
Detectable Effect ◽  
Acid Oxidation ◽  
Maternal Supplementation

Abstract Objectives Clofibrate as a therapeutic agent has been used for controlling hyperlipidemias of humans for more than 50 years. Its action, metabolism, half-life and excretion have been well documented in liver of adult humans and rodent species, but it has not been evaluated well in extrahepatic tissues in neonates as a stimulator of energy utilization. In this study, the role of maternal administration of clofibrate in development of renal fatty acid oxidation was evaluated using swine as a model. Methods A randomized complete block design was used with a total of 27 pregnant sows. The sows were fed standard gestation-lactation diets supplemented with either 0 (control), 0.25% or 0.5% clofibrate (w/w) from d 107 of gestation to d 7 of lactation. Fatty acid oxidation was measured in the presence or absence of carnitine (1 mM) or/and malonate (5 mM) in fresh kidney homogenates from piglets at d1, 7, 14 and 19 of age using 14C-oleic acid (1 mM) as substrate (9.9 mBq/mmol). Results Interactions (P &lt; 0.001) were observed between maternal clofibrate levels and postnatal age on 14C accumulation in CO2 (14CO2), acid soluble products (14C-ASP) and esterified products (14C-ESP). The 14CO2 increased by 1.3 fold from d1 to d7, but showed no differences between d7, 14 and 19 in pigs from the control sows. Maternal supplementation of clofibrate increased 14CO2 in pigs across all ages, but the increase was higher in pigs from sows fed 0.5% versus 0.25% clofibrate at d14. The 14C-ASP was 7-fold higher in d1 pigs from control sows than all other ages. Maternal supplementation of clofibrate increased 14C-ASP by 2 fold in pigs at d1, but had no detectable effect at d 7, 14 and 19. The 14C-ESP increased from d1 to d7 and decreased from d7 to d19 in pigs from control sows. Maternal supplementation of clofibrate had no detectable impact on 14C-ESP at d1, 14 and 19, but decreased 14C-ESP measured in d7 pigs. In vitro carnitine supplementation increased 14CO2 and malonate supplementation decreased 14CO2, but neither carnitine nor malonate altered 14C-ASP or 14C-ESP. Conclusions The stimulatory effect of maternal clofibrate on renal fatty acid metabolism in offspring is associated with the postnatal age, being greater at d1 and d7 than d14 and d19. Funding Sources USDA National Institute of Food and Agriculture.

scholarly journals The rheumatoid synovial environment alters fatty acid metabolism in human monocytes and enhances CCL20 secretion

Rheumatology ◽  
2019 ◽  
Vol 59 (4) ◽  
pp. 869-878 ◽  
Author(s):  
Lewis C Rodgers ◽  
John Cole ◽  
Kevin M Rattigan ◽  
Michael P Barrett ◽  
Nisha Kurian ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Human Monocyte ◽  
Transcriptional Analysis ◽  
Acid Oxidation ◽  
Human Monocytes ◽  
Blood Monocytes ◽  
Vitro Analysis

Abstract Objectives Fatty acid oxidation (FAO) and glycolysis have been implicated in immune regulation and activation of macrophages. However, investigation of human monocyte intracellular metabolism in the context of the hypoxic and inflammatory rheumatoid arthritis (RA) synovium is lacking. We hypothesized that exposure of monocytes to the hypoxic and inflammatory RA environment would have a profound impact on their metabolic state, and potential to contribute to disease pathology. Methods Human monocytes were isolated from buffy coats and exposed to hypoxia. Metabolic profiling of monocytes was carried out by LC-MS metabolomics. Inflammatory mediator release after LPS or RA-synovial fluid (RA-SF) stimulation was analysed by ELISA. FAO was inhibited by etomoxir or enhanced with exogenous carnitine supplementation. Transcriptomics of RA blood monocytes and RA-SF macrophages was carried out by microarray. Results Hypoxia exacerbated monocyte-derived CCL20 and IL-1β release in response to LPS, and increased glycolytic intermediates at the expense of carnitines. Modulation of carnitine identified a novel role for FAO in the production of CCL20 in response to LPS. Transcriptional analysis of RA blood monocytes and RA-SF macrophages revealed that fatty acid metabolism was altered and CCL20 increased when monocytes enter the synovial environment. In vitro analysis of monocytes showed that RA-SF increases carnitine abundance and CCL20 production in hypoxia, which was exacerbated by exogenous carnitine. Conclusion This work has revealed a novel inflammatory mechanism in RA that links FAO to CCL20 production in human monocytes, which could subsequently contribute to RA disease pathogenesis by promoting the recruitment of Th17 cells and osteoclastogenesis.

scholarly journals Maternal Supplementation of Clofibrate Stimulates Hepatic Fatty Acid Oxidation in Newborn Suckling Piglets

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 703-703
Author(s):  
Jinan Zhao ◽  
Brandon Pike ◽  
Jack Odle ◽  
Lin Xi
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Acid Oxidation ◽  
Standard Diet ◽  
Hepatic Fatty Acid ◽  
Food And Agriculture ◽  
Hepatic Fatty Acid Oxidation

Abstract Objectives To evaluate effects of maternal feeding of clofibrate, a PPARα agonist, on development of hepatic fatty acid metabolism in offspring using pig as a model. Methods Pregnant sows (N = 27) were randomly assigned into three treatment groups. Each group was fed a standard diet (3265 kcal ME/kg) supplemented with either 0, 0.25% or 5% clofibrate (w/w) from d 107 of gestation to d 7 of lactation. Liver tissue was collected from piglets at birth, d1, 7, 14 and 19. Fatty acid oxidation was examined in fresh homogenates using 1 mM [1–14C] oleic acid (9.9 mBq/mmol) as substrate. Oxidation was measured in the absence or presence of in vitro supplemented L-carnitine (1 mM) and/or malonate (5 mM). Results Clofibrate was not detected in piglet liver or sow milk. Interactions between clofibrate and postnatal age (P &lt; 0.001) on the 14C accumulation in 14CO2, acid soluble products (14C-ASP) and esterified products (14C-ESP) were observed. Accumulation in 14CO2 was not altered by piglet age in control sows; however, accumulation in 14C-ASP was higher at d14 and lower at d19 compared to d1. In contrast, maternal clofibrate increased 14CO2 by 100% and 14C-ASP by 80% in pigs at d1, and the increase was higher in pigs from sows given 0.5% versus 0.25% clofibrate. Accumulation in 14C-ESP in pigs from control sows increased from d1 to d14, but there was no difference detected between d14 and 19. Assessment of pigs from sows fed the 0.25% clofibrate dose revealed no impact on 14C-ESP, but the 0.5% dose increased 14C-ESP by 31%. No interaction was observed between clofibrate and the in vitro treatments (carnitine and malonate; P = 0.5). In vitro supplementation of carnitine increased radiolabel accumulation in CO2 by 60% and in ASP by 120%, but reduced 14C-ESP by 39% compared to control incubations. Supplementation of malonate reduced 14CO2 by 95% and 14C-ESP by 44%, but had no impact on 14C-ASP. Conclusions Maternal clofibrate enhances hepatic fatty acid metabolism in offspring, but the effect fades with postpartum age. The availability of carnitine in the milk could be a key element to support fatty acid oxidation in postnatal pigs. Funding Sources USDA National Institute of Food and Agriculture.

scholarly journals Central Acting Hsp10 Regulates Mitochondrial Function, Fatty Acid Metabolism, and Insulin Sensitivity in the Hypothalamus

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 711
Author(s):  
Kristina Wardelmann ◽  
Michaela Rath ◽  
José Pedro Castro ◽  
Sabine Blümel ◽  
Mareike Schell ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Fatty Acid ◽  
Mitochondrial Dysfunction ◽  
Fatty Acid Metabolism ◽  
Mitochondrial Function ◽  
Insulin Signaling ◽  
Acid Metabolism ◽  
Early Event ◽  
Hypothalamic Function

Mitochondria are critical for hypothalamic function and regulators of metabolism. Hypothalamic mitochondrial dysfunction with decreased mitochondrial chaperone expression is present in type 2 diabetes (T2D). Recently, we demonstrated that a dysregulated mitochondrial stress response (MSR) with reduced chaperone expression in the hypothalamus is an early event in obesity development due to insufficient insulin signaling. Although insulin activates this response and improves metabolism, the metabolic impact of one of its members, the mitochondrial chaperone heat shock protein 10 (Hsp10), is unknown. Thus, we hypothesized that a reduction of Hsp10 in hypothalamic neurons will impair mitochondrial function and impact brain insulin action. Therefore, we investigated the role of chaperone Hsp10 by introducing a lentiviral-mediated Hsp10 knockdown (KD) in the hypothalamic cell line CLU-183 and in the arcuate nucleus (ARC) of C57BL/6N male mice. We analyzed mitochondrial function and insulin signaling utilizing qPCR, Western blot, XF96 Analyzer, immunohistochemistry, and microscopy techniques. We show that Hsp10 expression is reduced in T2D mice brains and regulated by leptin in vitro. Hsp10 KD in hypothalamic cells induced mitochondrial dysfunction with altered fatty acid metabolism and increased mitochondria-specific oxidative stress resulting in neuronal insulin resistance. Consequently, the reduction of Hsp10 in the ARC of C57BL/6N mice caused hypothalamic insulin resistance with acute liver insulin resistance.

scholarly journals Lipid and glucose metabolism in hepatocyte cell lines and primary mouse hepatocytes: a comprehensive resource for in vitro studies of hepatic metabolism

2019 ◽  
Vol 316 (4) ◽  
pp. E578-E589 ◽  
Author(s):  
Shilpa R. Nagarajan ◽  
Moumita Paul-Heng ◽  
James R. Krycer ◽  
Daniel J. Fazakerley ◽  
Alexandra F. Sharland ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Glucose Metabolism ◽  
Cell Lines ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Primary Hepatocytes ◽  
Primary Mouse Hepatocytes ◽  
Primary Mouse ◽  
Mouse Hepatocytes

The liver is a critical tissue for maintaining glucose, fatty acid, and cholesterol homeostasis. Primary hepatocytes represent the gold standard for studying the mechanisms controlling hepatic glucose, lipid, and cholesterol metabolism in vitro. However, access to primary hepatocytes can be limiting, and therefore, other immortalized hepatocyte models are commonly used. Here, we describe substrate metabolism of cultured AML12, IHH, and PH5CH8 cells, hepatocellular carcinoma-derived HepG2s, and primary mouse hepatocytes (PMH) to identify which of these cell lines most accurately phenocopy PMH basal and insulin-stimulated metabolism. Insulin-stimulated glucose metabolism in PH5CH8 cells, and to a lesser extent AML12 cells, responded most similarly to PMH. Notably, glucose incorporation in HepG2 cells were 14-fold greater than PMH. The differences in glucose metabolic activity were not explained by differential protein expression of key regulators of these pathways, for example glycogen synthase and glycogen content. In contrast, fatty acid metabolism in IHH cells was the closest to PMHs, yet insulin-responsive fatty acid metabolism in AML12 and HepG2 cells was most similar to PMH. Finally, incorporation of acetate into intracellular-free cholesterol was comparable for all cells to PMH; however, insulin-stimulated glucose conversion into lipids and the incorporation of acetate into intracellular cholesterol esters were strikingly different between PMHs and all tested cell lines. In general, AML12 cells most closely phenocopied PMH in vitro energy metabolism. However, the cell line most representative of PMHs differed depending on the mode of metabolism being investigated, and so careful consideration is needed in model selection.

Abstract 15931: Glycogen Synthase Kinase-3α Plays a Critical Role in the Development of Cardiac Dysfunction During Obesity and Insulin Resistance Through Phosphorylation of Peroxisome Proliferator-Activated Receptor α

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Michinari Nakamura ◽  
Peiyong Zhai ◽  
Junichi Sadoshima
Keyword(s):  
Insulin Resistance ◽  
Cardiac Hypertrophy ◽  
Diastolic Dysfunction ◽  
Cardiac Dysfunction ◽  
Lipid Accumulation ◽  
Glycogen Synthase ◽  
Critical Role ◽  
Cardiac Metabolism ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Obesity and insulin resistance (IR) lead to impaired cardiac metabolism, resulting in cardiac dysfunction. However, the underlying mechanisms responsible for the development of cardiac dysfunction remain poorly understood. PPARα serves as a key regulator of fatty acid (FA) metabolism in the heart. GSK-3α, a serine/threonine kinase, was dephosphorylated at S21 and activated (2.0 fold, p<0.05) in the hearts of obese mice fed a high-fat diet (HFD) and ob/ob mice. To evaluate the functional significance of GSK-3α upregulation, wild-type (WT) and cardiac specific GSK-3α heterozygous knockout (cGSK-3α HKO) mice were fed a HFD for up to 14 weeks. There was no difference in the food intake or body weight change between WT and cGSK-3α HKO mice. However, cardiac hypertrophy and diastolic dysfunction observed in WT mice were significantly ameliorated in cGSK-3α HKO mice after HFD feeding (8.1± 0.6 and 6.5±0.5, LVW/TL; 24.8±0.9 and 16.6±0.8, deceleration time (DT), all p<0.05). FA oxidation (FAO) (0.81 fold) and ectopic lipid accumulation (Oil Red O staining) were significantly decreased in cGSK-3α HKO mice than in WT mice after HFD feeding. GSK-3α, but not GSK-3β, directly interacted with and phosphorylated PPARα at the ligand binding domain in cardiomyocytes (CMs) and in the heart. PPARα phosphorylation in the heart was significantly increased (2.1 fold, p<0.05) in response to HFD, but it was attenuated in cGSK-3α HKO mice (0.74 fold, p<0.05). Fenofibrate, a PPARα ligand, inhibited GSK-3α-induced PPARα phosphorylation (0.81 fold, p<0.05), reduced ectopic lipid accumulation, FAO (0.84 fold, p<0.05), and attenuated diastolic dysfunction (25.5±3.1 and 18.6±2.5, DT; 0.16±0.04 and 0.08±0.02, EDPVR, all p<0.05) in the heart of HFD fed mice. Collectively, these results suggest that GSK-3α increases PPARα activity through phosphorylation of PPARα, which is inhibited by Fenofibrate. Activation of GSK-3α and consequent phosphorylation of PPARα during obesity and IR could play an important role in the development of cardiac hypertrophy and diastolic dysfunction. Synthetic PPARα ligands inhibit GSK-3α-mediated phosphorylation of PPARα, thereby paradoxically attenuating excessive FA metabolism in cardiomyocytes.

scholarly journals Fatty acid oxidation inhibitor etomoxir suppresses tumor progression and induces cell cycle arrest via PPARγ-mediated pathway in bladder cancer

2019 ◽  
Vol 133 (15) ◽  
pp. 1745-1758 ◽  
Author(s):  
Songtao Cheng ◽  
Gang Wang ◽  
Yejinpeng Wang ◽  
Liwei Cai ◽  
Kaiyu Qian ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bladder Cancer ◽  
Fatty Acid ◽  
Tumor Progression ◽  
Cell Cycle Arrest ◽  
Fatty Acid Oxidation ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Acid Oxidation ◽  
Cycle Arrest

Abstract Tumor cells rely on aerobic glycolysis as their main energy resource (Warburg effect). Recent research has highlighted the importance of lipid metabolism in tumor progression, and certain cancers even turn to fatty acids as the main fuel. Related studies have identified alterations of fatty acid metabolism in human bladder cancer (BCa). Our microarray analysis showed that fatty acid metabolism was activated in BCa compared with normal bladder. The free fatty acid (FFA) level was also increased in BCa compared with paracancerous tissues. Inhibition of fatty acid oxidation (FAO) with etomoxir caused lipid accumulation, decreased adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) levels, suppressed BCa cell growth in vitro and in vivo, and reduced motility of BCa cells via affecting epithelial–mesenchymal transition (EMT)-related proteins. Furthermore, etomoxir induced BCa cell cycle arrest at G0/G1 phase through peroxisome proliferator-activated receptor (PPAR) γ-mediated pathway with alterations in fatty acid metabolism associated gene expression. The cell cycle arrest could be reversed by PPARγ antagonist GW9662. Taken together, our results suggest that inhibition of FAO with etomoxir may provide a novel avenue to investigate new therapeutic approaches to human BCa.

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