Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.99.3 (acyl-CoA dehydrogenase)
 1,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine whether expression of a nuclear gene encoding a mitochondrial fatty acid oxidation enzyme is regulated in parallel with skeletal muscle fibre-type-specific energy substrate preference, expression of the gene encoding medium-chain acyl-CoA dehydrogenase (MCAD) was delineated in canine latissimus dorsi muscle subjected to chronic motor nerve stimulation. In predominantly fast-twitch canine latissimus dorsi muscle, MCAD mRNA levels were regulated by chronic stimulation in a biphasic pattern. During the 1st wk of stimulation, steady-state MCAD mRNA levels decreased to 50% of unstimulated levels. MCAD mRNA levels began to increase during the 3rd wk of stimulation to reach a level 3.0-fold higher than levels in unstimulated contralateral control muscle by day 70. Immunodetectable MCAD mRNA levels throughout the stimulation period. The temporal pattern and magnitude of MCAD mRNA accumulation in response to muscle stimulation was distinct from that of mRNAs encoding other enzymes known to be regulated by this stimulus, including glyceraldehyde phosphate dehydrogenase, citrate synthase, and sarcoplasmic reticulum Ca-ATPase, but paralleled the protein levels of the peroxisome proliferator-activated receptor (PPAR), an orphan member of the nuclear hormone receptor superfamily known to regulate genes encoding fatty acid oxidation enzymes in liver. The skeletal muscle expression pattern of PPAR was also similar to that of MCAD in unstimulated rat skeletal muscles with distinct fiber-type compositions. These results demonstrate that a nuclear gene encoding a mitochondrial beta-oxidation enzyme is dynamically regulated in a pattern that parallels skeletal muscle fiber-type-specific energy substrate utilization and implicate an orphan nuclear receptor transcription factor as a candidate transducer of this response.
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PMID:Activation of a novel metabolic gene regulatory pathway by chronic stimulation of skeletal muscle. 896 42

Recent studies indicate that retinoid-mediated pathways play a pivotal role in cardiac morphogenesis and function. To identify proteins that serve as interacting partners of the retinoid X receptor alpha (RXRalpha) in heart, DNA-protein binding studies were performed with an RXR-responsive element (NRRE-1) derived from the medium chain acyl-CoA dehydrogenase gene promoter and nuclear protein extracts prepared from adult rat heart. NRRE-1 is a pleiotropic RXR-responsive element comprised of three potential recognition sites for class II members of the nuclear receptor superfamily. Gel mobility shift assays performed with an NRRE-1 probe in the absence or presence of bacterially overproduced RXRalpha and nuclear protein extracts prepared from adult rat heart, liver, or brain identified a cardiac-specific, RXR-dependent DNA-protein interaction. The NRRE-1-RXR.cardiac-enriched RXR-interacting protein (CERIP) complex exhibited a distinct mobility compared with NRRE-1-RXR.peroxisome proliferator-activated receptor, NRRE-1-RXR.retinoic acid receptor, or NRRE-1-RXR.thyroid receptor complexes. Mutational analysis demonstrated that two of the three potential binding half-sites of NRRE-1 (an everted repeat separated by an 8-base pair spacer) are required for the NRRE-1-RXR. CERIP interaction. Gel mobility shift assays demonstrated that CERIP interacted with RXRalpha and RXRgamma but not with RXRbeta, indicating a receptor subtypespecific binding preference and suggesting an RXR AB region-dependent interaction. The RXR.CERIP complex did not form on NRRE-1 when a mutant GST-RXRalpha fusion protein lacking the NH(2)-terminal AB region (but containing the receptor dimerization domain) of RXRalpha was added in place of the full-length RXRalpha, confirming a role for the AB region in the RXR. CERIP interaction. DNA-protein cross-linking studies demonstrated that CERIP is a DNA-binding protein of approximately 110 kDa. These results provide evidence for the existence of a cardiac-enriched DNA-binding protein that interacts with RXRalpha via the AB region and suggest a mechanism whereby cardiac retinoid signaling is controlled in an RXR subtype-specific manner.
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PMID:Evidence for a novel cardiac-enriched retinoid X receptor partner. 1046 3

Long-chain fatty acids are the most important substrates for the heart. In addition, they have been shown to affect signalling pathways and gene expression. To explore the effects of long-chain fatty acids on cardiac gene expression, neonatal rat ventricular myocytes were cultured for 48 h with either glucose (10 mm), fatty acids (palmitic and oleic acid, 0.25 mm each), or a combination of both as exogenous substrates. Exposure to fatty acids (both in the absence or presence of glucose) neither affected cellular morphology and protein content nor induced alterations in the expression of phenotypic marker genes like atrial natriuretic factor and the Ca-ATPase SERCA2. However, incubation with fatty acids (with or without glucose) resulted in up to 4-fold increases of the mRNA levels of fatty acid translocase (FAT/CD36), heart-type fatty acid-binding protein, acyl-CoA synthetase, and long-chain acyl-CoA dehydrogenase. In contrast, the expression of genes coding for proteins involved in glucose uptake and metabolism, i.e., glucose transporter GLUT4, hexokinase II, and glyceraldehyde 3-phosphate dehydrogenase, remained constant or even declined under these conditions. These changes corresponded with a 60% increase in cardiomyocyte fatty acid oxidation capacity. Interestingly, the peroxisome proliferator-activated receptor-alpha (PPARalpha)-ligand Wy 14,643, but not the PPARgamma-ligand ciglitazone, also resulted in increased mRNA levels of genes involved in fatty acid metabolism. In conclusion, fatty acids specifically and co-ordinately up-regulate transcription of genes coding for proteins involved in cardiac fatty acid transport and metabolism, most likely through activation of PPARalpha.
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PMID:Long-chain fatty acid-induced changes in gene expression in neonatal cardiac myocytes. 1062

Retinoid x receptor alpha (RXRalpha) serves as an active partner of peroxisome proliferator-activated receptor (PPARalpha). In order to dissect the functional role of RXRalpha and PPARalpha in PPARalpha-mediated pathways, the hepatocyte RXRalpha-deficient mice have been challenged with physiological and pharmacological stresses, fasting and Wy14,643, respectively. The data demonstrate that RXRalpha and PPARalpha deficiency are different in several aspects. At the basal untreated level, RXRalpha deficiency resulted in marked induction of apolipoprotein A-I and C-III (apoA-I and apoC-III) mRNA levels and serum cholesterol and triglyceride levels, which was not found in PPARalpha-null mice. Fasting-induced PPARalpha activation was drastically prevented in the absence of hepatocyte RXRalpha. Wy14,643-mediated pleiotropic effects were also altered due to the absence of hepatocyte RXRalpha. Hepatocyte RXRalpha deficiency did not change the basal acyl-CoA oxidase, medium chain acyl-CoA dehydrogenase, and malic enzyme mRNA levels. However, the inducibility of those genes by Wy14,643 was markedly reduced in the mutant mouse livers. In contrast, the basal cytochrome P450 4A1, liver fatty acid-binding protein, and apoA-I and apoC-III mRNA levels were significantly altered in the mutant mouse livers, but the regulatory effect of Wy14,643 on expression of those genes remained the same. Wy14,643-induced hepatomegaly was partially inhibited in hepatocyte RXRalpha-deficient mice. Wy14,643-induced hepatocyte peroxisome proliferation was preserved in the absence of hepatocyte RXRalpha. These data suggested that in comparison to PPARalpha, hepatocyte RXRalpha has its unique role in lipid homeostasis and that the effect of RXRalpha, -beta, and -gamma is redundant in certain aspects.
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PMID:Peroxisome proliferator-activated receptor alpha-mediated pathways are altered in hepatocyte-specific retinoid X receptor alpha-deficient mice. 1086 95

The alpha isoform of peroxisome proliferator-activated receptor (PPARalpha), which is highly expressed in the kidney, can stimulate the expression of genes that are involved in fatty acid catabolism and therefore might be involved in the control of renal fatty acid beta-oxidation. PPARalpha expression and its regulation in the immature kidney are not well documented. This study delineated the developmental pattern of PPARalpha expression in the rat kidney cortex and the medulla between postnatal days 10 and 30 and investigated the role of glucocorticoids in regulating PPARalpha expression. In the cortex, PPARalpha mRNA and protein increased 2- and 1.8-fold, respectively, from 10 to 21 d and then decreased 1.5- and 2.4-fold from 21 to 30 d. In the medulla, PPARalpha mRNA and protein increased continuously 3.3- and 2.4-fold, respectively. It is shown here that acute treatment by dexamethasone of 10-d-old rats precociously induced a 4- to 6-fold increase in PPARalpha mRNA and a 1.8-fold increase in protein within 6 h in each part of the kidney. Chronic injection of dexamethasone for 3 d also increased PPARalpha mRNA 3.8- and 2.2-fold in the cortex and the medulla, respectively, with a 1.5- and 2-fold increase in protein. Furthermore, adrenalectomy prevented the increases in PPARalpha mRNA and protein in both the cortex and the medulla between postnatal days 16 and 21, and these could be restored by dexamethasone treatment. Finally, with the use of an established renal cell line, it was shown that glucocorticoids stimulate gene expression of PPARalpha and of medium chain acyl-CoA dehydrogenase (MCAD, a PPARalpha target gene) 2- to 4-fold and 1.5-fold, respectively, and that addition of fatty acids in the culture media led to a 2.2-fold increase in MCAD mRNA. Altogether, these results demonstrated that glucocorticoids are potent regulators of PPARalpha development in the immature kidney and that these hormones act in concert with fatty acids to regulate MCAD gene expression in renal cells.
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PMID:PPARalpha gene expression in the developing rat kidney: role of glucocorticoids. 1137 42

Tamoxifen is a potent antagonist of estrogen, and hepatic steatosis is a frequent complication in adjuvant tamoxifen for breast cancer. Recently, aromatase-deficient (ArKO, Ar-/-) mice lacking intrinsic estrogen was developed and the molecular mechanism involved in progression of massive hepatic steatosis in estrogen-deficiency was elucidated; impairment in hepatic fatty acid beta-oxidation of peroxisomes, microsomes and mitochondria. This impairment is latent, but is potentially serious, because hepatic energy supply depends greatly on fatty acid beta-oxidation. Therefore in the present study, we tried to conquer impaired hepatic fatty acid beta-oxidation by administrating bezafibrate, a potent peroxisome proliferator, to Ar-/- mice through activating fatty acid beta-oxidation via the peroxisome proliferator activated receptor-alpha mediated signaling pathway. Northern blot analysis of Ar-/- mice liver revealed a significant restoration of mRNA expression of very long fatty acyl-CoA synthetase in peroxisome, peroxisomal fatty acyl-CoA oxidase, and medium-chain acyl-CoA dehydrogenase in mitochondria, essential enzymes in fatty acid beta-oxidation by administration of bezafibrate. Severe hepatic steatosis observed in Ar-/- mice regressed dramatically. Consistent findings were obtained in the in vitro assays of fatty acid beta-oxidation activity. These findings demonstrate that bezafibrate is capable of restoring impaired fatty acid beta-oxidation in vivo via the peroxisome proliferator-activated receptor-alpha mediated signaling pathway and is potent enough to regress severe hepatic steatosis in mice deficient in intrinsic estrogen.
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PMID:Aromatase-deficient (ArKO) mice are retrieved from severe hepatic steatosis by peroxisome proliferator administration. 1192 13

We investigated whether decreased responsiveness of the heart to physiological increases in fatty acid availability results in lipid accumulation and lipotoxic heart disease. Lean and obese Zucker rats were either fed ad libitum or fasted overnight. Fasting increased plasma nonesterified fatty acid levels in both lean and obese rats, although levels were greatest in obese rats regardless of nutritional status. Despite increased fatty acid availability, the mRNA transcript levels of peroxisome proliferator-activated receptor (PPAR)-alpha-regulated genes were similar in fed lean and fed obese rat hearts. Fasting increased expression of all PPAR-alpha -regulated genes in lean Zucker rat hearts, whereas, in obese Zucker rat hearts, muscle carnitine palmitoyltransferase and medium-chain acyl-CoA dehydrogenase were unaltered with fasting. Rates of oleate oxidation were similar for hearts from fed rats. However, fasting increased rates of oleate oxidation only in hearts from lean rats. Dramatic lipid deposition occurred within cardiomyocytes of obese, but not lean, Zucker rats upon fasting. Cardiac output was significantly depressed in hearts isolated from obese rats compared with lean rats, regardless of nutritional status. Fasting increased cardiac output in hearts of lean rats only. Thus, the heart's inability to increase fatty acid oxidation in proportion to increased fatty acid availability is associated with lipid accumulation and contractile dysfunction of the obese Zucker rat.
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PMID:Impaired long-chain fatty acid oxidation and contractile dysfunction in the obese Zucker rat heart. 1214 75

Tamoxifen is a potent antagonist of estrogen, and hepatic steatosis is a frequent complication in adjuvant tamoxifen for breast cancer. Impaired hepatic FA beta-oxidation in peroxisomes, microsomes, and mitochondria results in progression of massive hepatic steatosis in estrogen deficiency. This impairment, although latent, is potentially serious: About 3% of the general population in the United States is now suffering from nonalcoholic steatohepatitis associated with obesity and hyperlipidemia. Therefore, in the present study we tried to restore impaired hepatic FA beta-oxidation by administering a novel statin, pitavastatin, to aromatase-deficient (Ar-/-) mice defective in intrinsic estrogen synthesis. Northern blot analysis of Ar-/- mice liver revealed a significant restoration of mRNA expression of essential enzymes involved in FA beta-oxidation such as very long fatty acyl-CoA synthetase in peroxisome, peroxisomal fatty acyl-CoA oxidase, and medium-chain acyl-CoA dehydrogenase. Severe hepatic steatosis observed in Ar-/- mice substantially regressed. Consistent findings were obtained in the in vitro assays of FA beta-oxidation activity. These findings demonstrate that pitavastatin is capable of restoring impaired FA beta-oxidation in vivo via the peroxisome proliferator-activated receptor-alpha-mediated signaling pathway and is potent enough to ameliorate severe hepatic steatosis in mice deficient in intrinsic estrogen.
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PMID:Pitavastatin ameliorates severe hepatic steatosis in aromatase-deficient (Ar-/-) mice. 1288 Jan 7

A well balanced body energy budget controlled by limitation of calorie uptake and/or increment of energy expenditure, which is typically achieved by proper physical exercise, is most effective against obesity and diabetes mellitus. Recently, peroxisome proliferator-activated receptor (PPAR) gamma, a member of the nuclear receptor, and its cofactors have been shown to be involved in lipid metabolism and in the control of energy expenditure. Here we show that PPARgamma coactivator 1 (PGC-1) beta functions as ERRL1 (for ERR ligand 1), which can bind and activate orphan ERRs (estrogen receptor-related receptors) in vitro. Consistently, PGC-1beta/ERRL1 transgenic mice exhibit increased expression of the medium-chain acyl CoA dehydrogenase, a known ERR target and a pivotal enzyme of mitochondrial beta-oxidation in skeletal muscle. As a result, the PGC-1beta/ERRL1 mice show a state similar to an athlete; namely, the mice are hyperphagic and of elevated energy expenditure and are resistant to obesity induced by a high-fat diet or by a genetic abnormality. These results demonstrate that PGC-1beta/ERRL1 can function as a protein ligand of ERR, and that its level contributes to the control of energy balance in vivo, and provide a strategy for developing novel antiobesity drugs.
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PMID:PPARgamma coactivator 1beta/ERR ligand 1 is an ERR protein ligand, whose expression induces a high-energy expenditure and antagonizes obesity. 1453 Mar 91

Previous studies demonstrated that during cisplatin-induced acute renal failure, there is a significant reduction in proximal tubule fatty acid oxidation. We now report on the effects of peroxisome proliferator-activated receptor-alpha (PPAR alpha) ligand Wy-14643 (WY) on the abnormalities of medium chain fatty acid oxidation and pyruvate dehydrogenase complex (PDC) activity in kidney tissue of cisplatin-treated mice. Cisplatin causes a significant reduction in mRNA levels and enzyme activity of mitochondrial medium chain acyl-CoA dehydrogenase (MCAD). PPAR alpha ligand WY ameliorated cisplatin-induced acute renal failure and prevented cisplatin-induced reduction of mRNA levels and enzyme activity of MCAD. In contrast, in cisplatin-treated PPAR alpha null mice, WY did not protect kidney function and did not reverse cisplatin-induced decreased expression of MCAD. Cisplatin inhibited renal PDC activity before the development of acute tubular necrosis, and PDC inhibition was reversed by pretreatment with PPAR alpha agonist WY. Cisplatin also induced increased mRNA and protein levels of pyruvate dehydrogenase kinase-4 (PDK4), and PPAR alpha ligand WY prevented cisplatin-induced increased expression of PDK4 protein levels in wild-type mice. We conclude that PPAR alpha agonists have therapeutic potential for cisplatin-induced acute renal failure. Use of PPAR alpha ligands prevents acute tubular necrosis by ameliorating cisplatin-induced inhibition of two distinct metabolic processes, MCAD-mediated fatty acid oxidation and PDC activity.
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PMID:PPAR alpha ligand protects during cisplatin-induced acute renal failure by preventing inhibition of renal FAO and PDC activity. 1461 80


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