Loss of perilipin 2 in cultured myotubes enhances lipolysis and redirects the metabolic energy balance from glucose oxidation towards fatty acid oxidation

Introduction: Trimetazidine (TMZ) is an anti-anginal drug that has been widely used in Europe and Asia. The TMZ can optimize energy metabolism via inhibition of long-chain 3-ketoacyl CoA thiolase (3-KAT) in the heart, with subsequent decrease in fatty acid oxidation and stimulation of glucose oxidation. However, the mechanism by which TMZ aids in cardioprotection against ischemic injury has not been characterized. Hypothesis: AMP-activated protein kinase (AMPK) is an energy sensor that control ATP supply from substrate metabolism and protect heart from energy stress. TMZ changes the cardiac AMP/ATP ratio via modulating fatty acid oxidation, thereby it may trigger AMPK signaling cascade that contribute to protection heart from ischemia/reperfusion (I/R) injury. Methods: The mouse in vivo regional ischemia and reperfusion by the ligation of the left anterior descending coronary artery (LAD) were used for determination of myocardial infarction. The infarct size was compared between C57BL/6J WT mice and AMPK kinase dead (KD) transgenic mice with or without TMZ treatment. The ex vivo working heart perfusion system was used to monitor the effect of TMZ on glucose oxidation and fatty acid oxidation in the heart. Results: TMZ treatment significantly stimulates cardiac AMPK and extracellular signal-regulated kinase (ERK) signaling pathways (p<0.05 vs. vehicle group). The administration of TMZ reduces myocardial infarction size in WT C57BL/6J hearts, the reduction of myocardial infarction size by TMZ in AMPK KD hearts was significantly impaired versus WT hearts (p<0.05). Intriguingly, the administration of ERK inhibitor, PD 98059, to AMPK KD mice abolished the cardioprotection of TMZ against I/R injury. The ex vivo working heart perfusion data demonstrated that TMZ treatment significantly activates AMPK signaling and modulating the substrate metabolism by shifting fatty acid oxidation to glucose oxidation during reperfusion, leading to reduction of oxidative stress in the I/R hearts. Conclusions: Both AMPK and ERK signaling pathways mediate the cardioprotection of TMZ against ischemic injury. The metabolic benefits of TMZ for angina patients could be due to the activation of energy sensor AMPK in the heart by TMZ administration.

Download Full-text

Acetylation and succinylation contribute to maturational alterations in energy metabolism in the newborn heart

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00900.2015 ◽

2016 ◽

Vol 311 (2) ◽

pp. H347-H363 ◽

Cited By ~ 34

Author(s):

Arata Fukushima ◽

Osama Abo Alrob ◽

Liyan Zhang ◽

Cory S. Wagg ◽

Tariq Altamimi ◽

...

Keyword(s):

Fatty Acid ◽

Energy Metabolism ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Acid Oxidation ◽

Amino Acid Synthesis ◽

Oxidation Rates ◽

Cardiac Energy Metabolism ◽

Cardiac Energy ◽

The Impact

Dramatic maturational changes in cardiac energy metabolism occur in the newborn period, with a shift from glycolysis to fatty acid oxidation. Acetylation and succinylation of lysyl residues are novel posttranslational modifications involved in the control of cardiac energy metabolism. We investigated the impact of changes in protein acetylation/succinylation on the maturational changes in energy metabolism of 1-, 7-, and 21-day-old rabbit hearts. Cardiac fatty acid β-oxidation rates increased in 21-day vs. 1- and 7-day-old hearts, whereas glycolysis and glucose oxidation rates decreased in 21-day-old hearts. The fatty acid oxidation enzymes, long-chain acyl-CoA dehydrogenase (LCAD) and β-hydroxyacyl-CoA dehydrogenase (β-HAD), were hyperacetylated with maturation, positively correlated with their activities and fatty acid β-oxidation rates. This alteration was associated with increased expression of the mitochondrial acetyltransferase, general control of amino acid synthesis 5 like 1 (GCN5L1), since silencing GCN5L1 mRNA in H9c2 cells significantly reduced acetylation and activity of LCAD and β-HAD. An increase in mitochondrial ATP production rates with maturation was associated with the decreased acetylation of peroxisome proliferator-activated receptor-γ coactivator-1α, a transcriptional regulator for mitochondrial biogenesis. In addition, hypoxia-inducible factor-1α, hexokinase, and phosphoglycerate mutase expression declined postbirth, whereas acetylation of these glycolytic enzymes increased. Phosphorylation rather than acetylation of pyruvate dehydrogenase (PDH) increased in 21-day-old hearts, accounting for the low glucose oxidation postbirth. A maturational increase was also observed in succinylation of PDH and LCAD. Collectively, our data are the first suggesting that acetylation and succinylation of the key metabolic enzymes in newborn hearts play a crucial role in cardiac energy metabolism with maturation. Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/acetylation-control-of-energy-metabolism-in-newborn-hearts/ .

Download Full-text

Reduced Liver-Specific PGC1a Increases Susceptibility for Short-Term Diet-induced Weight Gain in Male Mice

10.1101/2020.12.04.412460 ◽

2020 ◽

Author(s):

E. Matthew Morris ◽

Roberto D. Noland ◽

Michael E. Ponte ◽

Michelle L. Montonye ◽

Julie A. Christianson ◽

...

Keyword(s):

Fatty Acid ◽

Weight Gain ◽

Energy Metabolism ◽

Energy Balance ◽

Fatty Acid Oxidation ◽

Positive Energy ◽

Acid Oxidation ◽

Male Mice ◽

Short Term

AbstractCentral integration of peripheral neural signals is one mechanism by which systemic energy homeostasis is regulated. Previous work described increased acute food intake following chemical reduction of hepatic fatty acid oxidation and ATP levels, which was prevented by common hepatic branch vagotomy (HBV). However, possible offsite actions of the chemical compounds confound the precise role of liver energy metabolism. Herein, we used a liver-specific PGC1a heterozygous (LPGC1a) mouse model, with associated reductions in mitochondrial fatty acid oxidation and respiratory capacity, to assess the role of liver energy metabolism in systemic energy homeostasis. LPGC1a male mice have 70% greater high-fat/high-sucrose (HFHS) diet-induced weight gain and 35% greater positive energy balance compared to wildtype (WT) (p<0.05). The greater energy balance was associated with altered feeding behavior and lower activity energy expenditure during HFHS in LPGC1a males. Importantly, no differences in HFHS-induced weight gain or energy metabolism was observed between female WT and LPGC1a mice. WT and LPGC1a mice underwent sham or HBV to assess whether vagal signaling was involved in HFHS-induced weight gain of male LPGC1a mice. HBV increased HFHS-induced weight gain (85%, p<0.05) in male WT, but not LPGC1a mice. As above, sham LPGC1a males gain 70% more weight during short-term HFHS feeding than sham WT (p<0.05). These data demonstrate a sexspecific role of reduced liver energy metabolism in acute diet-induced weight gain, and the need of more nuanced assessment of the role of vagal signaling in short-term diet-induced weight gain.Key Points SummaryReduced liver PGC1a expression results in reduced mitochondrial fatty acid oxidation and respiratory capacity in male mice.Male mice with reduced liver PGC1a expression (LPGC1a) demonstrate greater short-term high-fat/high-sucrose diet-induced weight gain compared to wildtype.Greater positive energy balance during HFHS feeding in male LPGC1a mice is associated with altered food intake patterns and reduced activity energy expenditure.Female LPGC1a mice do not have differences in short-term HFHS-induced body weight gain or energy metabolism compared to wildtype.Disruption of vagal signaling through common hepatic branch vagotomy increases short-term HFHS-induced weight gain in male wildtype mice, but does not alter male LPGC1a weight gain.

Download Full-text

Isoproterenol stimulates 5′-AMP-activated protein kinase and fatty acid oxidation in neonatal hearts

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00186.2010 ◽

2010 ◽

Vol 299 (4) ◽

pp. H1135-H1145 ◽

Cited By ~ 12

Author(s):

Jagdip S. Jaswal ◽

Chad R. Lund ◽

Wendy Keung ◽

Donna L. Beker ◽

Ivan M. Rebeyka ◽

...

Keyword(s):

Fatty Acid ◽

Protein Kinase ◽

Fatty Acid Oxidation ◽

Energy Demand ◽

Glucose Oxidation ◽

Acid Oxidation ◽

Acetyl Coa ◽

Lactate Oxidation ◽

Major Energy Source ◽

Amp Activated Protein Kinase

Isoproterenol increases phosphorylation of LKB, 5′-AMP-activated protein kinase (AMPK), and acetyl-CoA carboxylase (ACC), enzymes involved in regulating fatty acid oxidation. However, inotropic stimulation selectively increases glucose oxidation in adult hearts. In the neonatal heart, fatty acid oxidation becomes a major energy source, while glucose oxidation remains low. This study tested the hypothesis that increased energy demand imposed by isoproterenol originates from fatty acid oxidation, secondary to increased LKB, AMPK, and ACC phosphorylation. Isolated working hearts from 7-day-old rabbits were perfused with Krebs solution (0.4 mM palmitate, 11 mM glucose, 0.5 mM lactate, and 100 mU/l insulin) with or without isoproterenol (300 nM). Isoproterenol increased myocardial O2 consumption (in J·g dry wt−1·min−1; 11.0 ± 1.4, n = 8 vs. 7.5 ± 0.8, n = 6, P < 0.05), and the phosphorylation of LKB (in arbitrary density units; 0.87 ± 0.09, n = 6 vs. 0.59 ± 0.08, n = 6, P < 0.05), AMPK (0.82 ± 0.08, n = 6 vs. 0.51 ± 0.06, n = 6, P < 0.05), and ACC-β (1.47 ± 0.14, n = 6 vs. 0.97 ± 0.07, n = 6, P < 0.05), with a concomitant decrease in malonyl-CoA levels (in nmol/g dry wt; 0.9 ± 0.9, n = 8 vs. 7.5 ± 1.3, n = 8, P < 0.05) and increase in palmitate oxidation (in nmol·g dry wt−1·min−1; 272 ± 45, n = 8 vs. 114 ± 9, n = 6, P < 0.05). Glucose and lactate oxidation were increased (in nmol·g dry wt−1·min−1; 253 ± 75, n = 8 vs. 63 ± 15, n = 9, P < 0.05 and 246 ± 43, n = 8 vs. 82 ± 11, n = 6, P < 0.05, respectively), independent of alterations in pyruvate dehydrogenase phosphorylation, but occurred secondary to a decrease in acetyl-CoA content and acetyl-CoA-to-free CoA ratio. As acetyl-CoA levels decrease in response to isoproterenol, despite an acceleration of the rates of palmitate and carbohydrate oxidation, these data suggest net rates of acetyl-CoA utilization exceed the net rates of acetyl-CoA generation.

Download Full-text

Abstract 653: Muscle Ring Finger-1 (MuRF1) Expression Shifts Cardiomyocyte Substrate Utilization from Fatty Acids to Glucose

Circulation ◽

10.1161/circ.116.suppl_16.ii_120-c ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Monte S Willis ◽

Jon Schisler ◽

Holly McDonough ◽

Cam Patterson

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Relative Proportion ◽

Substrate Utilization ◽

Acid Oxidation ◽

Protective Mechanism ◽

Dependent Manner ◽

Dose Dependent

Previous work has suggested that MuRF1, a cardiac-specific protein, regulates metabolism by its interactions with proteins that regulate ATP transport, glycolysis, and the electron transport chain. We recently identified that MuRF1 is cardioprotective in ischemia reperfusion injury. In the current study, we investigated the effects of MuRF1 expression on metabolic substrate utilization and found that MuRF1 shifts substrate utilization from fatty acids to glucose in a dose-dependent manner. Isolated neonatal ventricular cardiomyocytes were treated with an adenovirus expressing MuRF1 (Ad.MuRF1) or GFP (Ad.GFP) at a range of 0–25 MOI (Multiplicity Of Infection). 14C-Oleate or 14C-glucose were added to cells for 1 hour and 14C-CO2 release was determined using the CO2-trapping method. Trapped 14CO2 and acid soluble metabolites were used to calculate total fatty acid oxidation. Cardiomyocytes treated with 5–25 MOI Ad.MuRF1 demonstrated a dose dependent decrease in fatty acid oxidation of 10.5 +/− 2.3(5 MOI), 8.5 +/− 1.9 (10 MOI), 6.6 +/− 1.6 (15 MOI), and 5.1 +/− 1.3 (25 MOI) nmol oleate/mg protein/h. Compared with control cardiomyocytes treated with 5–25 MOI Ad.GFP (average of 5–25 MOI=13.5 +/− 0.7 nmol oleate/mg protein/h), this represents a 22.2%– 62.2% decrease in fatty acid oxidation. Inversely, glucose oxidation increased with increasing MuRF1 expression. Cardiomyocytes infected with 25 MOI Ad.MuRF1 oxidized 184% more glucose (28.9 +/− 4.6 nmol glucose/mg protein/h) compared to control cells treated with 25 MOI Ad.GFP (15.7 +/− 1.3 nmol glucose/mg protein/h). Increasing MuRF1 expression resulted in no net gain or loss of calculated ATP production (1699 +/− 157 vs. 1480 +/− 188 nmol ATP/mg protein/h). The co-utilization of glucose and fatty acids as substrates for the production of ATP allows the heart to adapt to both environmental stress and disease. Increasing the relative proportion of glucose oxidation in relationship to fatty acids is a known protective mechanism during cardiac stress, and may represent one mechanism by which MuRF1 is cardioprotective.

Download Full-text

Epinephrine increases ATP production in hearts by preferentially increasing glucose metabolism

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1994.267.5.h1862 ◽

1994 ◽

Vol 267 (5) ◽

pp. H1862-H1871 ◽

Cited By ~ 27

Author(s):

R. L. Collins-Nakai ◽

D. Noseworthy ◽

G. D. Lopaschuk

Keyword(s):

Fatty Acid ◽

Glucose Metabolism ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Contractile Function ◽

Pyruvate Dehydrogenase Complex ◽

Active Form ◽

Acid Oxidation ◽

Complex Activity ◽

Atp Production

Although epinephrine is widely used clinically, its effect on myocardial energy substrate preference in the intact heart has yet to be clearly defined. We determined the effects of epinephrine on glucose and fatty acid metabolism in isolated working rat hearts perfused with 11 mM glucose, 0.4 mM palmitate, and 100 muU/ml insulin at an 11.5-mmHg left atrial preload and a 60-mmHg aortic afterload. Glycolysis and glucose oxidation were measured in hearts perfused with [5–3H]glucose and [U-14C]glucose, whereas fatty acid oxidation was measured in hearts perfused with [1–14C]palmitate. Addition of 1 microM epinephrine resulted in a 53% increase in the heart rate-developed pressure product. Glycolysis increased dramatically following addition of epinephrine (a 272% increase), as did glucose oxidation (a 410% increase). In contrast, fatty acid oxidation increased by only 10%. Epinephrine treatment did not increase the amount of oxygen required to produce an equivalent amount of ATP; however, epinephrine did increase the uncoupling between glycolysis and glucose oxidation in these fatty acid-perfused hearts, resulting in a significant increase in H+ production from glucose metabolism. Overall ATP production in epinephrine-treated hearts increased 59%. The contribution of glucose (glycolysis and glucose oxidation) to ATP production increased from 13 to 36%, which was accompanied by a reciprocal decrease in the contribution of fatty acid oxidation to ATP production from 83 to 63%. The increase in glucose oxidation was accompanied by a significant increase in pyruvate dehydrogenase complex activity in the active form. We conclude that the increase in ATP required for contractile function following epinephrine treatment occurs through a preferential increase in glucose use.

Download Full-text

Level of satiety: in vitro energy metabolism in brain during hypophagic and hyperphagic body weight recovery

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.257.6.r1322 ◽

1989 ◽

Vol 257 (6) ◽

pp. R1322-R1327 ◽

Cited By ~ 2

Author(s):

T. R. Kasser ◽

R. B. Harris ◽

R. J. Martin

Keyword(s):

Weight Loss ◽

Body Weight ◽

Fatty Acid ◽

Food Intake ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Area Postrema ◽

Tube Feeding ◽

Acid Oxidation

Rates of in vitro glucose and fatty acid oxidation were examined in four brain sites during hypophagic and hyperphagic recovery of normal body weight. Rats were fed 40, 100, or 160% of normal intake, via gastric intubation, for 3 wk. Another group of rats was starved until body weight loss was equivalent to weight loss in 40%-fed rats. Groups of rats were killed at the conclusion of tube feeding or fasting and at specific periods during recovery of body weight. Brain sites examined were the ventrolateral hypothalamus (VLH), ventromedial hypothalamus (VMH), a caudal brain stem site encompassing the area postrema-nucleus of the solitary tract (AP-NTS), and cortex. During recovery, rats previously fed 160% of normal intake (anorectic) maintained low rates of VLH fatty acid oxidation and were hypophagic until most excess fat was depleted. Conversely, rats previously fed 40% of normal intake (hungry) maintained high rates of VLH fatty acid oxidation and were hyperphagic until most deficient fat was repleted. Rats previously starved maintained high rates of VLH fatty acid oxidation during hyperphagic recovery, although levels of VLH fatty acid oxidation and food intake were initially low on refeeding. Rates of glucose oxidation in the brain sites examined did not relate well to energy balance status and the needed adjustments in food intake. The results indicated that the level of glucose oxidation in the VLH and AP-NTS responded to the level of energy immediately coming into the system (food intake).(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

Stimulatory effects of leptin and muscle contraction on fatty acid metabolism are not additive

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2001.281.1.e122 ◽

2001 ◽

Vol 281 (1) ◽

pp. E122-E129 ◽

Cited By ~ 9

Author(s):

R. Lau ◽

W. D. Blinn ◽

A. Bonen ◽

D. J. Dyck

Keyword(s):

Fatty Acid ◽

Lipid Metabolism ◽

Muscle Contraction ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Acid Oxidation ◽

Muscle Lipid ◽

Triacylglycerol Hydrolysis ◽

Plasma Leptin ◽

Resting Muscle

Leptin has been shown to acutely stimulate fatty acid oxidation and triacylglycerol hydrolysis in skeletal muscle. These effects are similar to those induced by muscle contraction alone. Several studies have demonstrated that, during aerobic exercise, plasma leptin concentrations are well maintained; however, none has examined whether the stimulatory effects of leptin and contraction on muscle lipid metabolism are additive. This is the first study to examine the direct effect of leptin on lipid and carbohydrate (CHO) metabolism in isolated oxidative muscle over a range of contraction intensities. We examined the effect of leptin (10 μg/ml) on the synthesis and degradation of muscle lipid pools [phospholipid (PL), diacylglycerol (DG), triacylglycerol (TG)] and palmitate oxidation in isolated resting and contracting (2, 8, and 20 tetani/min) soleus muscles. At rest, leptin increased fatty acid oxidation (+40%, P < 0.05) and TG hydrolysis (+47%, P < 0.05), while blunting TG esterification (−20%, P < 0.05). Glucose oxidation was unaffected at rest in the presence of leptin. During tetanic contraction, fatty acid oxidation (+20–114%, P < 0.05) and TG esterification (+19–33%, P < 0.05) as well as net TG utilization (+23%, P < 0.05) were all significantly increased. However, leptin was without further effect on any of these parameters during contraction. Net utilization of intramuscular glycogen, as well as glucose oxidation, was unaffected during contraction by leptin. The findings of the present study indicate that leptin has an important influence on lipid metabolism in resting muscle, but not during contraction.

Download Full-text

Regulation of fatty acid oxidation and glucose metabolism in rat soleus muscle: effects of AICAR

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2001.281.2.e335 ◽

2001 ◽

Vol 281 (2) ◽

pp. E335-E340 ◽

Cited By ~ 58

Author(s):

Virendar K. Kaushik ◽

Martin E. Young ◽

David J. Dean ◽

Theodore G. Kurowski ◽

Asish K. Saha ◽

...

Keyword(s):

Fatty Acid ◽

Protein Kinase ◽

Glucose Uptake ◽

Fatty Acid Oxidation ◽

Glucose Oxidation ◽

Acid Oxidation ◽

Malonyl Coa ◽

Rat Soleus Muscle ◽

Amp Activated Protein Kinase ◽

Fasted Rats

Previous studies have shown that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), a cell-permeable activator of AMP-activated protein kinase, increases the rate of fatty acid oxidation in skeletal muscle of fed rats. The present study investigated the mechanism by which this occurs and, in particular, whether changes in the activity of malonyl-CoA decarboxylase (MCD) and the β-isoform of acetyl-CoA carboxylase (ACCβ) are involved. In addition, the relationship between changes in fatty acid oxidation induced by AICAR and its effects on glucose uptake and metabolism was examined. In incubated soleus muscles isolated from fed rats, AICAR (2 mM) increased fatty acid oxidation (90%) and decreased ACCβ activity (40%) and malonyl-CoA concentration (50%); however, MCD activity was not significantly altered. In soleus muscles from overnight-fasted rats, AICAR decreased ACCβ activity (40%), as it did in fed rats; however, it had no effect on the already high rate of fatty acid oxidation or the low malonyl-CoA concentration. In keeping with its effect on fatty acid oxidation, AICAR decreased glucose oxidation by 44% in fed rats but did not decrease glucose oxidation in fasted rats. It had no effect on glucose oxidation when fatty acid oxidation was inhibited by 2-bromopalmitate. Surprisingly, AICAR did not significantly increase glucose uptake or assayable AMP-activated protein kinase activity in incubated soleus muscles from fed or fasted rats. These results indicate that, in incubated rat soleus muscle, 1) AICAR does not activate MCD or stimulate glucose uptake as it does in extensor digitorum longus and epitrochlearis muscles, 2) the ability of AICAR to increase fatty acid oxidation and diminish glucose oxidation and malonyl-CoA concentration is dependent on the nutritional status of the rat, and 3) the ability of AICAR to diminish assayable ACC activity is independent of nutritional state.

Download Full-text