scholarly journals Chronic Hypoxia Enhances β-Oxidation-Dependent Electron Transport via Electron Transferring Flavoproteins

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 172 ◽  
Author(s):  
Dominik C. Fuhrmann ◽  
Catherine Olesch ◽  
Nina Kurrle ◽  
Frank Schnütgen ◽  
Sven Zukunft ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Fatty Acid ◽  
Electron Transport ◽  
Mitochondrial Respiration ◽  
Chronic Hypoxia ◽  
Acute Hypoxia ◽  
Acid Synthesis ◽  
Acid Oxidation ◽  
Fatty Acid Production ◽  
Consumption Rates

Hypoxia poses a stress to cells and decreases mitochondrial respiration, in part by electron transport chain (ETC) complex reorganization. While metabolism under acute hypoxia is well characterized, alterations under chronic hypoxia largely remain unexplored. We followed oxygen consumption rates in THP-1 monocytes during acute (16 h) and chronic (72 h) hypoxia, compared to normoxia, to analyze the electron flows associated with glycolysis, glutamine, and fatty acid oxidation. Oxygen consumption under acute hypoxia predominantly demanded pyruvate, while under chronic hypoxia, fatty acid- and glutamine-oxidation dominated. Chronic hypoxia also elevated electron-transferring flavoproteins (ETF), and the knockdown of ETF–ubiquinone oxidoreductase lowered mitochondrial respiration under chronic hypoxia. Metabolomics revealed an increase in citrate under chronic hypoxia, which implied glutamine processing to α-ketoglutarate and citrate. Expression regulation of enzymes involved in this metabolic shunting corroborated this assumption. Moreover, the expression of acetyl-CoA carboxylase 1 increased, thus pointing to fatty acid synthesis under chronic hypoxia. Cells lacking complex I, which experienced a markedly impaired respiration under normoxia, also shifted their metabolism to fatty acid-dependent synthesis and usage. Taken together, we provide evidence that chronic hypoxia fuels the ETC via ETFs, increasing fatty acid production and consumption via the glutamine-citrate-fatty acid axis.

Abstract 328: Med13 regulates cardiac metabolism

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Kedryn K Baskin ◽  
Chad E Grueter ◽  
Christine M Kusminski ◽  
Philipp E Scherer ◽  
Rhonda Bassel-Duby ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Fatty Acid ◽  
Glucose Uptake ◽  
Fatty Acid Oxidation ◽  
Electron Flow ◽  
Krebs Cycle ◽  
Cardiac Metabolism ◽  
Acid Oxidation ◽  
Intermediary Metabolites ◽  
Consumption Rates

Background: The heart is a metabolic organ that primarily utilizes fatty acids as energy substrate. While it is well established that the heart is metabolically flexible, the transcriptional network regulating cardiac metabolism is only partially understood. We have previously demonstrated that cardiac overexpression of Med13, a component of the Mediator Complex that regulates transcription, results in a lean phenotype with enhanced basal metabolic rates. We now investigate the mechanisms contributing to metabolic changes in mice with cardiac over-expression of Med13(Med13cTg). Methods and Results: Cardiac fludeoxyglucose (18F-FDG)-PET imaging analysis revealed that Med13cTg hearts take up more glucose than wild type littermates. To determine pathways responsible for enhanced glucose uptake, ventricles from Med13cTg mice were subjected to RNA-seq and metabolomic analysis. The expression of fatty acid oxidation genes was decreased in Med13cTg hearts, accompanied by an increase in acyl CoA and a decrease in acetyl CoA. These data suggest that beta oxidation is decreased in Med13cTg hearts. Mitochondria function was therefore determined in Med13cTg hearts by performing electron-flow analyses and assessing oxygen consumption rates. Indeed, oxygen consumption rates were decreased in mitochondria isolated from Med13cTg hearts. Expression of Krebs Cycle genes and corresponding intermediary metabolites were also decreased in Med13cTg hearts, suggesting decreased flux through this pathway as well. Conclusions: Overexpression of Med13 in the heart increases glucose uptake and decreases fatty acid oxidation in the heart. We speculate that Med13 transcriptionally regulates key mediators of cardiac metabolism. The mechanisms by which this occurs are currently under investigation.

scholarly journals Increased thermogenesis by a noncanonical pathway in ANGPTL3/8-deficient mice

2018 ◽  
Vol 115 (6) ◽  
pp. E1249-E1258 ◽  
Author(s):  
Serena Banfi ◽  
Viktoria Gusarova ◽  
Jesper Gromada ◽  
Jonathan C. Cohen ◽  
Helen H. Hobbs
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Metabolic Cost ◽  
Acid Synthesis ◽  
Energy Utilization ◽  
Acid Oxidation ◽  
Induced Hyperthermia ◽  
Expression Of Genes ◽  
Brown Adipose ◽  
Consumption Rates

Dietary triglyceride (TG) is the most efficient energy substrate. It is processed and stored at substantially lower metabolic cost than is protein or carbohydrate. In fed animals, circulating TGs are preferentially routed for storage to white adipose tissue (WAT) by angiopoietin-like proteins 3 (A3) and 8 (A8). Here, we show that mice lacking A3 and A8 (A3−/−A8−/− mice) have decreased fat mass and a striking increase in temperature (+1 °C) in the fed (but not fasted) state, without alterations in food intake or physical activity. Subcutaneous WAT (WAT-SQ) from these animals had morphologic and metabolic changes characteristic of beiging. O2 consumption rates (OCRs) and expression of genes involved in both fatty acid synthesis and fatty acid oxidation were increased in WAT-SQ of A3−/−A8−/− mice, but not in their epididymal or brown adipose tissue (BAT). The hyperthermic response to feeding was blocked by maintaining A3−/−A8−/− mice at thermoneutrality or by treating with a β3-adrenergic receptor (AR) antagonist. To determine if sympathetic stimulation was sufficient to increase body temperature in A3−/−A8−/− mice, WT and A3−/−A8−/− animals were maintained at thermoneutrality and then treated with a β3-AR agonist; treatment induced hyperthermia in A3−/−A8−/−, but not WT, mice. Antibody-mediated inactivation of both circulating A3 and A8 induced hyperthermia in WT mice. Together, these data indicate that A3 and A8 are essential for efficient storage of dietary TG and that disruption of these genes increases feeding-induced thermogenesis and energy utilization.

scholarly journals Progesterone receptor membrane component 1 reduces cardiac steatosis and lipotoxicity via activation of fatty acid oxidation and mitochondrial respiration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sang R. Lee ◽  
Jun H. Heo ◽  
Seong Lae Jo ◽  
Globinna Kim ◽  
Su Jung Kim ◽  
...  
Keyword(s):  
Heart Failure ◽  
Fatty Acid ◽  
Progesterone Receptor ◽  
Fatty Acid Oxidation ◽  
Mitochondrial Respiration ◽  
De Novo Lipogenesis ◽  
Acid Oxidation ◽  
Membrane Component ◽  
Markers Of Inflammation ◽  
Receptor Membrane

AbstractObesity is implicated in cardiovascular disease and heart failure. When fatty acids are transported to and not adequately oxidized in cardiac cells, they accumulate, causing lipotoxicity in the heart. Since hepatic progesterone receptor membrane component 1 (Pgrmc1) suppressed de novo lipogenesis in a previous study, it was questioned whether cardiac Pgrmc1 protects against lipotoxicity. Hence, we focused on the role of cardiac Pgrmc1 in basal (Resting), glucose-dominant (Refed) and lipid-dominant high-fat diet (HFD) conditions. Pgrmc1 KO mice showed high FFA levels and low glucose levels compared to wild-type (WT) mice. Pgrmc1 KO mice presented low number of mitochondrial DNA copies in heart, and it was concomitantly observed with low expression of TCA cycle genes and oxidative phosphorylation genes. Pgrmc1 absence in heart presented low fatty acid oxidation activity in all conditions, but the production of acetyl-CoA and ATP was in pronounced suppression only in HFD condition. Furthermore, HFD Pgrmc1 KO mice resulted in high cardiac fatty acyl-CoA levels and TG level. Accordingly, HFD Pgrmc1 KO mice were prone to cardiac lipotoxicity, featuring high levels in markers of inflammation, endoplasmic reticulum stress, oxidative stress, fibrosis, and heart failure. In vitro study, it was also confirmed that Pgrmc1 enhances rates of mitochondrial respiration and fatty acid oxidation. This study is clinically important because mitochondrial defects in Pgrmc1 KO mice hearts represent the late phase of cardiac failure.

scholarly journals miR-21-5p regulates mitochondrial respiration and lipid content in H9C2 cells

2019 ◽  
Vol 316 (3) ◽  
pp. H710-H721 ◽  
Author(s):  
Victoria L. Nasci ◽  
Sandra Chuppa ◽  
Lindsey Griswold ◽  
Kathryn A. Goodreau ◽  
Ranjan K. Dash ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acid ◽  
Palmitic Acid ◽  
Fatty Acid Oxidation ◽  
Lipid Content ◽  
Mitochondrial Respiration ◽  
Acid Oxidation ◽  
H9c2 Cells ◽  
Cellular Lipid ◽  
Transfected Cells

Cardiovascular-related pathologies are the single leading cause of death in patients with chronic kidney disease (CKD). Previously, we found that a 5/6th nephrectomy model of CKD leads to an upregulation of miR-21-5p in the left ventricle, targeting peroxisome proliferator-activated receptor-α and altering the expression of numerous transcripts involved with fatty acid oxidation and glycolysis. In the present study, we evaluated the potential for knockdown or overexpression of miR-21-5p to regulate lipid content, lipid peroxidation, and mitochondrial respiration in H9C2 cells. Cells were transfected with anti-miR-21-5p (40 nM), pre-miR-21-5p (20 nM), or the appropriate scrambled oligonucleotide controls before lipid treatment in culture or as part of the Agilent Seahorse XF fatty acid oxidation assay. Overexpression of miR-21-5p attenuated the lipid-induced increase in cellular lipid content, whereas suppression of miR-21-5p augmented it. The abundance of malondialdehyde, a product of lipid peroxidation, was significantly increased with lipid treatment in control cells but attenuated in pre-miR-21-5p-transfected cells. This suggests that miR-21-5p reduces oxidative stress. The cellular oxygen consumption rate (OCR) was increased in both pre-miR-21-5p- and anti-miR-21-5p-transfected cells. Levels of intracellular ATP were significantly higher in anti-mR-21-5p-transfected cells. Pre-miR-21-5p blocked additional increases in OCR in response to etomoxir and palmitic acid. Conversely, anti-miR-21-5p-transfected cells exhibited reduced OCR with both etomoxir and palmitic acid, and the glycolytic capacity was concomitantly reduced. Together, these results indicate that overexpression of miR-21-5p attenuates both lipid content and lipid peroxidation in H9C2 cells. This likely occurs by reducing cellular lipid uptake and utilization, shifting cellular metabolism toward reliance on the glycolytic pathway. NEW & NOTEWORTHY Both overexpression and suppression of miR-21-5p augment basal and maximal mitochondrial respiration. Our data suggest that reliance on glycolytic and fatty acid oxidation pathways can be modulated by the abundance of miR-21-5p within the cell. miR-21-5p regulation of mitochondrial respiration can be modulated by extracellular lipids.

scholarly journals High glucose levels reduce fatty acid oxidation and increase triglyceride accumulation in human placenta

2013 ◽  
Vol 305 (2) ◽  
pp. E205-E212 ◽  
Author(s):  
Francisco Visiedo ◽  
Fernando Bugatto ◽  
Viviana Sánchez ◽  
Irene Cózar-Castellano ◽  
Jose L. Bartha ◽  
...  
Keyword(s):  
Fatty Acid ◽  
High Glucose ◽  
De Novo ◽  
Acid Synthesis ◽  
Acid Oxidation ◽  
Glucose Levels ◽  
Triglyceride Accumulation ◽  
Triglyceride Content ◽  
Low Glucose ◽  
Cpt I

Placentas of women with gestational diabetes mellitus (GDM) exhibit an altered lipid metabolism. The mechanism by which GDM is linked to alterations in placental lipid metabolism remains obscure. We hypothesized that high glucose levels reduce mitochondrial fatty acid oxidation (FAO) and increase triglyceride accumulation in human placenta. To test this hypothesis, we measured FAO, fatty acid esterification, de novo fatty acid synthesis, triglyceride levels, and carnitine palmitoyltransferase activities (CPT) in placental explants of women with GDM or no pregnancy complication. In women with GDM, FAO was reduced by ∼30% without change in mitochondrial content, and triglyceride content was threefold higher than in the control group. Likewise, in placental explants of women with no complications, high glucose levels reduced FAO by ∼20%, and esterification increased linearly with increasing fatty acid concentrations. However, de novo fatty acid synthesis remained unchanged between high and low glucose levels. In addition, high glucose levels increased triglyceride content approximately twofold compared with low glucose levels. Furthermore, etomoxir-mediated inhibition of FAO enhanced esterification capacity by ∼40% and elevated triglyceride content 1.5-fold in placental explants of women, with no complications. Finally, high glucose levels reduced CPT I activity by ∼70% and phosphorylation levels of acetyl-CoA carboxylase by ∼25% in placental explants of women, with no complications. We reveal an unrecognized regulatory mechanism on placental fatty acid metabolism by which high glucose levels reduce mitochondrial FAO through inhibition of CPT I, shifting flux of fatty acids away from oxidation toward the esterification pathway, leading to accumulation of placental triglycerides.

scholarly journals Palmitoleic acid (16:1n7) increases oxygen consumption, fatty acid oxidation and ATP content in white adipocytes

2018 ◽  
Vol 17 (1) ◽  
Author(s):  
Maysa M. Cruz ◽  
Andressa B. Lopes ◽  
Amanda R. Crisma ◽  
Roberta C. C. de Sá ◽  
Wilson M. T. Kuwabara ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Palmitoleic Acid ◽  
Acid Oxidation ◽  
Atp Content ◽  
White Adipocytes

scholarly journals Proteomics study of the effect of high-fat diet on rat liver

2019 ◽  
Vol 122 (9) ◽  
pp. 1062-1072 ◽  
Author(s):  
Jian Sang ◽  
Hengxian Qu ◽  
Ruixia Gu ◽  
Dawei Chen ◽  
Xia Chen ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
High Fat Diet ◽  
Acid Synthesis ◽  
High Energy ◽  
The Body ◽  
Acid Oxidation ◽  
High Fat ◽  
Bioinformatics Analyses ◽  
Fat Diets

AbstractExcessive intake of high-energy diets is an important cause of most obesity. The intervention of rats with high-fat diet can replicate the ideal animal model for studying the occurrence of human nutritional obesity. Proteomics and bioinformatics analyses can help us to systematically and comprehensively study the effect of high-fat diet on rat liver. In the present study, 4056 proteins were identified in rat liver by using tandem mass tag. A total of 198 proteins were significantly changed, of which 103 were significantly up-regulated and ninety-five were significantly down-regulated. These significant differentially expressed proteins are primarily involved in lipid metabolism and glucose metabolism processes. The intake of a high-fat diet forces the body to maintain physiological balance by regulating these key protein spots to inhibit fatty acid synthesis, promote fatty acid oxidation and accelerate fatty acid degradation. The present study enriches our understanding of metabolic disorders induced by high-fat diets at the protein level.

scholarly journals Acetyl-CoA carboxylase inhibition by ND-630 reduces hepatic steatosis, improves insulin sensitivity, and modulates dyslipidemia in rats

2016 ◽  
Vol 113 (13) ◽  
pp. E1796-E1805 ◽  
Author(s):  
Geraldine Harriman ◽  
Jeremy Greenwood ◽  
Sathesh Bhat ◽  
Xinyi Huang ◽  
Ruiying Wang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Liver Disease ◽  
Insulin Sensitivity ◽  
Fatty Liver ◽  
Hepatic Steatosis ◽  
Fatty Acid Synthesis ◽  
Fatty Liver Disease ◽  
Acid Synthesis ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase

Simultaneous inhibition of the acetyl-CoA carboxylase (ACC) isozymes ACC1 and ACC2 results in concomitant inhibition of fatty acid synthesis and stimulation of fatty acid oxidation and may favorably affect the morbidity and mortality associated with obesity, diabetes, and fatty liver disease. Using structure-based drug design, we have identified a series of potent allosteric protein–protein interaction inhibitors, exemplified by ND-630, that interact within the ACC phosphopeptide acceptor and dimerization site to prevent dimerization and inhibit the enzymatic activity of both ACC isozymes, reduce fatty acid synthesis and stimulate fatty acid oxidation in cultured cells and in animals, and exhibit favorable drug-like properties. When administered chronically to rats with diet-induced obesity, ND-630 reduces hepatic steatosis, improves insulin sensitivity, reduces weight gain without affecting food intake, and favorably affects dyslipidemia. When administered chronically to Zucker diabetic fatty rats, ND-630 reduces hepatic steatosis, improves glucose-stimulated insulin secretion, and reduces hemoglobin A1c (0.9% reduction). Together, these data suggest that ACC inhibition by representatives of this series may be useful in treating a variety of metabolic disorders, including metabolic syndrome, type 2 diabetes mellitus, and fatty liver disease.

scholarly journals Assessment of myocardial metabolic flexibility and work efficiency in human type 2 diabetes using 16-[18F]fluoro-4-thiapalmitate, a novel PET fatty acid tracer

2016 ◽  
Vol 310 (6) ◽  
pp. E452-E460 ◽  
Author(s):  
K. J. Mather ◽  
G. D. Hutchins ◽  
K. Perry ◽  
W. Territo ◽  
R. Chisholm ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Oxygen Consumption ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Metabolic Flexibility ◽  
Work Efficiency ◽  
Myocardial Fatty Acid ◽  
Fuel Selection

Altered myocardial fuel selection likely underlies cardiac disease risk in diabetes, affecting oxygen demand and myocardial metabolic flexibility. We investigated myocardial fuel selection and metabolic flexibility in human type 2 diabetes mellitus (T2DM), using positron emission tomography to measure rates of myocardial fatty acid oxidation {16-[18F]fluoro-4-thia-palmitate (FTP)} and myocardial perfusion and total oxidation ([11C]acetate). Participants underwent paired studies under fasting conditions, comparing 3-h insulin + glucose euglycemic clamp conditions (120 mU·m−2·min−1) to 3-h saline infusion. Lean controls ( n = 10) were compared with glycemically controlled volunteers with T2DM ( n = 8). Insulin augmented heart rate, blood pressure, and stroke index in both groups (all P < 0.01) and significantly increased myocardial oxygen consumption ( P = 0.04) and perfusion ( P = 0.01) in both groups. Insulin suppressed available nonesterified fatty acids ( P < 0.0001), but fatty acid concentrations were higher in T2DM under both conditions ( P < 0.001). Insulin-induced suppression of fatty acid oxidation was seen in both groups ( P < 0.0001). However, fatty acid oxidation rates were higher under both conditions in T2DM ( P = 0.003). Myocardial work efficiency was lower in T2DM ( P = 0.006) and decreased in both groups with the insulin-induced increase in work and shift in fuel utilization ( P = 0.01). Augmented fatty acid oxidation is present under baseline and insulin-treated conditions in T2DM, with impaired insulin-induced shifts away from fatty acid oxidation. This is accompanied by reduced work efficiency, possibly due to greater oxygen consumption with fatty acid metabolism. These observations suggest that improved fatty acid suppression, or reductions in myocardial fatty acid uptake and retention, could be therapeutic targets to improve myocardial ischemia tolerance in T2DM.

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