Acetyl-CoA derived from hepatic mitochondrial fatty acid β-oxidation aggravates inflammation by enhancing p65 acetylation

ABSTRACTIn many eukaryotes, the carnitine shuttle plays a key role in intracellular transport of acyl moieties. Fatty acid-grownSaccharomyces cerevisiaecells employ this shuttle to translocate acetyl units into their mitochondria. Mechanistically, the carnitine shuttle should be reversible, but previous studies indicate that carnitine shuttle-mediated export of mitochondrial acetyl units to the yeast cytosol does not occurin vivo. This apparent unidirectionality was investigated by constitutively expressing genes encoding carnitine shuttle-related proteins in an engineeredS. cerevisiaestrain, in which cytosolic acetyl coenzyme A (acetyl-CoA) synthesis could be switched off by omitting lipoic acid from growth media. Laboratory evolution of this strain yielded mutants whose growth on glucose, in the absence of lipoic acid, wasl-carnitine dependent, indicating thatin vivoexport of mitochondrial acetyl units to the cytosol occurred via the carnitine shuttle. The mitochondrial pyruvate dehydrogenase complex was identified as the predominant source of acetyl-CoA in the evolved strains. Whole-genome sequencing revealed mutations in genes involved in mitochondrial fatty acid synthesis (MCT1), nuclear-mitochondrial communication (RTG2), and encoding a carnitine acetyltransferase (YAT2). Introduction of these mutations into the nonevolved parental strain enabledl-carnitine-dependent growth on glucose. This study indicates intramitochondrial acetyl-CoA concentration and constitutive expression of carnitine shuttle genes as key factors in enablingin vivoexport of mitochondrial acetyl units via the carnitine shuttle.IMPORTANCEThis study demonstrates, for the first time, thatSaccharomyces cerevisiaecan be engineered to employ the carnitine shuttle for export of acetyl moieties from the mitochondria and, thereby, to act as the sole source of cytosolic acetyl-CoA. Further optimization of this ATP-independent mechanism for cytosolic acetyl-CoA provision can contribute to efficient, yeast-based production of industrially relevant compounds derived from this precursor. The strains constructed in this study, whose growth on glucose depends on a functional carnitine shuttle, provide valuable models for further functional analysis and engineering of this shuttle in yeast and other eukaryotes.

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Altered hepatic mitochondrial fatty acid oxidation and ketogenesis in endotoxic rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1990.259.4.e498 ◽

1990 ◽

Vol 259 (4) ◽

pp. E498-E505 ◽

Cited By ~ 4

Author(s):

N. Takeyama ◽

Y. Itoh ◽

Y. Kitazawa ◽

T. Tanaka

Keyword(s):

Oxygen Consumption ◽

Fatty Acid ◽

Maximum Velocity ◽

Oxidative Capacity ◽

Acid Oxidation ◽

Acetyl Coa ◽

Mitochondrial Fatty Acid Oxidation ◽

Malonyl Coa ◽

Mitochondrial Fatty Acid ◽

Cpt I

Rat hepatic mitochondrial function, including oxidative phosphorylation, fatty acid oxidative capacity, kinetic parameters of carnitine palmitoyltransferase I (CPT I), and sensitivity of CPT I to malonyl-CoA inhibition were studied in vitro in isolated mitochondria following Escherichia coli lipopolysaccharide (LPS). The hepatic mitochondrial CPT I in LPS-treated rats showed a lower apparent maximum velocity (Vmax) for palmitoyl-CoA and Ki for malonyl-CoA without changes in apparent Km for palmitoyl-CoA. The rate of oxygen consumption or end-product formation of palmitoyl-L-carnitine and octanoate was not altered, but the rate of CPT I-dependent palmitoyl-CoA (plus L-carnitine) oxidation was reduced by LPS, when acetyl-CoA produced via beta-oxidation was directed toward citrate. When acetyl-CoA was directed to acetoacetate, the oxygen consumption rates of palmitoyl-L-carnitine and palmitoyl-CoA (plus L-carnitine) were decreased by LPS, although mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase activity was not altered. These results indicate that hepatic mitochondria isolated from LPS-treated rats show lower ketogenic and long-chain acyl-CoA oxidative capacity than those of fasted controls, and inhibition of ketogenesis is elicited at a site distal to CPT I in addition to reduction in CPT I activity.

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Role of CoA and acetyl-CoA in regulating cardiac fatty acid and glucose oxidation

Biochemical Society Transactions ◽

10.1042/bst20140094 ◽

2014 ◽

Vol 42 (4) ◽

pp. 1043-1051 ◽

Cited By ~ 36

Author(s):

Osama Abo Alrob ◽

Gary D. Lopaschuk

Keyword(s):

Heart Failure ◽

Fatty Acid ◽

Fatty Acid Oxidation ◽

Oxidative Enzymes ◽

Acid Oxidation ◽

Acetyl Coa ◽

Malonyl Coa ◽

Mitochondrial Fatty Acid ◽

Cardiac Energy Metabolism ◽

Cardiac Energy

CoA (coenzyme A) and its derivatives have a critical role in regulating cardiac energy metabolism. This includes a key role as a substrate and product in the energy metabolic pathways, as well as serving as an allosteric regulator of cardiac energy metabolism. In addition, the CoA ester malonyl-CoA has an important role in regulating fatty acid oxidation, secondary to inhibiting CPT (carnitine palmitoyltransferase) 1, a key enzyme involved in mitochondrial fatty acid uptake. Alterations in malonyl-CoA synthesis by ACC (acetyl-CoA carboxylase) and degradation by MCD (malonyl-CoA decarboxylase) are important contributors to the high cardiac fatty acid oxidation rates seen in ischaemic heart disease, heart failure, obesity and diabetes. Additional control of fatty acid oxidation may also occur at the level of acetyl-CoA involvement in acetylation of mitochondrial fatty acid β-oxidative enzymes. We find that acetylation of the fatty acid β-oxidative enzymes, LCAD (long-chain acyl-CoA dehydrogenase) and β-HAD (β-hydroxyacyl-CoA dehydrogenase) is associated with an increase in activity and fatty acid oxidation in heart from obese mice with heart failure. This is associated with decreased SIRT3 (sirtuin 3) activity, an important mitochondrial deacetylase. In support of this, cardiac SIRT3 deletion increases acetylation of LCAD and β-HAD, and increases cardiac fatty acid oxidation. Acetylation of MCD is also associated with increased activity, decreases malonyl-CoA levels and an increase in fatty acid oxidation. Combined, these data suggest that malonyl-CoA and acetyl-CoA have an important role in mediating the alterations in fatty acid oxidation seen in heart failure.

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Peroxisomal Fatty Acid Oxidation Is a Substantial Source of the Acetyl Moiety of Malonyl-CoA in Rat Heart

Journal of Biological Chemistry ◽

10.1074/jbc.m400162200 ◽

2004 ◽

Vol 279 (19) ◽

pp. 19574-19579 ◽

Cited By ~ 52

Author(s):

Aneta E. Reszko ◽

Takhar Kasumov ◽

France David ◽

Kathryn A. Jobbins ◽

Katherine R. Thomas ◽

...

Keyword(s):

Fatty Acid ◽

Fatty Acid Oxidation ◽

Acid Oxidation ◽

Acetyl Coa ◽

Mitochondrial Fatty Acid Oxidation ◽

Fatty Acid Chain ◽

Rat Hearts ◽

Malonyl Coa ◽

Mitochondrial Fatty Acid ◽

Perfused Rat Hearts

Little is known about the sources of acetyl-CoA used for the synthesis of malonyl-CoA, a key regulator of mitochondrial fatty acid oxidation in the heart. In perfused rat hearts, we previously showed that malonyl-CoA is labeled from both carbohydrates and fatty acids. This study was aimed at assessing the mechanisms of incorporation of fatty acid carbons into malonyl-CoA. Rat hearts were perfused with glucose, lactate, pyruvate, and a fatty acid (palmitate, oleate or docosanoate). In each experiment, substrates were13C-labeled to yield singly or/and doubly labeled acetyl-CoA. The mass isotopomer distribution of malonyl-CoA was compared with that of the acetyl moiety of citrate, which reflects mitochondrial acetyl-CoA. In the presence of labeled glucose or lactate/pyruvate, the13C labeling of malonyl-CoA was up to 2-fold lower than that of mitochondrial acetyl-CoA. However, in the presence of a fatty acid labeled in its first acetyl moiety, the13C labeling of malonyl-CoA was up to 10-fold higher than that of mitochondrial acetyl-CoA. The labeling of malonyl-CoA and of the acetyl moiety of citrate is compatible with peroxisomal β-oxidation forming C12and C14acyl-CoAs and contributing >50% of the fatty acid-derived acetyl groups that end up in malonyl-CoA. This fraction increases with the fatty acid chain length. By supplying acetyl-CoA for malonyl-CoA synthesis, peroxisomal β-oxidation may participate in the control of mitochondrial fatty acid oxidation in the heart. In addition, this pathway may supply some acyl groups used in protein acylation, which is increasingly recognized as an important regulatory mechanism for many biochemical processes.

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Inhibition by acetyl-CoA of hepatic carnitine acyltransferase and fatty acid oxidation

Biochemical Journal ◽

10.1042/bj2160499 ◽

1983 ◽

Vol 216 (2) ◽

pp. 499-502 ◽

Cited By ~ 6

Author(s):

K McCormick ◽

V J Notar-Francesco ◽

K Sriwatanakul

Keyword(s):

Fatty Acid ◽

Fatty Acid Oxidation ◽

Acid Oxidation ◽

Acetyl Coa ◽

Mitochondrial Fatty Acid Oxidation ◽

Acyltransferase Activity ◽

Carnitine Acyltransferase ◽

Mitochondrial Transfer ◽

Mitochondrial Fatty Acid ◽

Chain Acyl

At micromolar concentrations, acetyl-CoA inhibited hepatic carnitine acyltransferase activity and mitochondrial fatty acid oxidation. The inhibitory effects were not nearly as potent on a molar basis as those of malonyl-CoA; nevertheless, the cytosolic concentrations of acetyl-CoA, as yet unknown, may be sufficient (greater than 30 microM) to curtail appreciably the mitochondrial transfer of long-chain acyl-CoA units and fatty acid oxidation. Hence acetyl-CoA may also partially regulate hepatic ketogenesis.

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Peroxisomal oxidation of erucic acid suppresses mitochondrial fatty acid oxidation by stimulating malonyl-CoA formation in the rat liver

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.013583 ◽

2020 ◽

Vol 295 (30) ◽

pp. 10168-10179 ◽

Cited By ~ 1

Author(s):

Xiaocui Chen ◽

Lin Shang ◽

Senwen Deng ◽

Ping Li ◽

Kai Chen ◽

...

Keyword(s):

Fatty Acid ◽

Erucic Acid ◽

Hepatic Steatosis ◽

Fatty Acid Oxidation ◽

Acid Oxidation ◽

Acetyl Coa ◽

Mitochondrial Fatty Acid Oxidation ◽

High Erucic Acid ◽

Malonyl Coa ◽

Mitochondrial Fatty Acid

Feeding of rapeseed (canola) oil with a high erucic acid concentration is known to cause hepatic steatosis in animals. Mitochondrial fatty acid oxidation plays a central role in liver lipid homeostasis, so it is possible that hepatic metabolism of erucic acid might decrease mitochondrial fatty acid oxidation. However, the precise mechanistic relationship between erucic acid levels and mitochondrial fatty acid oxidation is unclear. Using male Sprague–Dawley rats, along with biochemical and molecular biology approaches, we report here that peroxisomal β-oxidation of erucic acid stimulates malonyl-CoA formation in the liver and thereby suppresses mitochondrial fatty acid oxidation. Excessive hepatic uptake and peroxisomal β-oxidation of erucic acid resulted in appreciable peroxisomal release of free acetate, which was then used in the synthesis of cytosolic acetyl-CoA. Peroxisomal metabolism of erucic acid also remarkably increased the cytosolic NADH/NAD+ ratio, suppressed sirtuin 1 (SIRT1) activity, and thereby activated acetyl-CoA carboxylase, which stimulated malonyl-CoA biosynthesis from acetyl-CoA. Chronic feeding of a diet including high-erucic-acid rapeseed oil diminished mitochondrial fatty acid oxidation and caused hepatic steatosis and insulin resistance in the rats. Of note, administration of a specific peroxisomal β-oxidation inhibitor attenuated these effects. Our findings establish a cross-talk between peroxisomal and mitochondrial fatty acid oxidation. They suggest that peroxisomal oxidation of long-chain fatty acids suppresses mitochondrial fatty acid oxidation by stimulating malonyl-CoA formation, which might play a role in fatty acid–induced hepatic steatosis and related metabolic disorders.

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