Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.4.1.2 (acetyl-CoA carboxylase)
 2,876 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study, the beneficial effects of proteasome inhibitor treatment in reducing ethanol-induced steatosis were investigated. A microarray analysis was performed on the liver of rats injected with PS-341 (Bortezomib, Velcade), and the results showed that proteasome inhibitor treatment significantly reduced the mRNA expression of SREBP-1c, and the downstream lipogenic enzymes, such as fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), which catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, the rate-limiting step in fatty acid synthesis. ELOVL6, which is responsible for fatty acids long chain elongation, was also significantly downregulated by proteasome inhibitor treatment. Moreover, PS-341 administration significantly reduced the expression of acyl-glycerol-3-phosphate acyltransferase (AGPAT), and diacylglycerol acyltransferase (DGAT), enzyme involved in triacylglycerol (TAG) synthesis. Finally, PS-341 was found to downregulate the enzyme 3-hydroxy-3-methylglutaryl-CoenzymeA synthase (HMG-CoA synthase) that is responsible for cholesterol synthesis. Proteasome inhibitor was also found to play a role in intestinal lipid adsorption because apolipoproteins A (apoA-I, apoAII, apoA-IV and ApoCIII) were downregulated by proteasome inhibitor treatment, especially ApoA-II that is known to be a marker of alcohol consumption. Proteasome inhibitor treatment also decreased apobec-1 complementation factor (ACF) leading to lower level of editing and production of ApoB protein. Moreover apolipoprotein C-III, a major component of chylomicrons was significantly downregulated. However, lipoprotein lipase (Lpl) and High density lipoprotein binding protein (Hdlbp) mRNA levels were increased by proteasome inhibitor treatment. These results suggested that proteasome inhibitor treatment could be used to reduce the alcohol-enhanced lipogenesis and alcohol-induced liver steatosis. A morphologic analysis, performed on the liver of rats fed ethanol for one month and treated with PS-341, showed that proteasome inhibitor treatment significantly decreased ethanol-induced liver steatosis. SREBP-1c, FAS and ACC were increased by ethanol feeding alone, but were significantly decreased when proteasome inhibitor was administered to rats fed ethanol. Our results also show that both mRNA and protein levels of these lipogenic enzymes, up regulated by ethanol, were then downregulated when proteasome inhibitor was administered to rats fed ethanol. It was also confirmed that alcohol feeding caused an increase in AGPAT and DGAT, which was prevented by proteasome inhibitor treatment of the animal fed ethanol. Chronic alcohol feeding did not affect the gene expression of HMG-CoA synthase. However, PS341 administration significantly reduced the HMG-CoA synthase mRNA levels, confirming the results obtained with the microarray analysis. C/EBP transcription factors alpha (CCAAT/enhancer-binding protein alpha) has been shown to positively regulate SREBP-1c mRNA expression, thus regulating lipogenesis. Proteasome inhibition caused a decrease in C/EBP alpha mRNA expression, indicating that C/EBP downregulation may be the mechanism by which proteasome inhibitor treatment reduced lipogenesis. In conclusion, our results indicate that proteasome activity is not only involved in downregulating fatty acid synthesis and triacylglycerol synthesis, but also cholesterol synthesis and intestinal lipid adsorption. Proteasome inhibitor, administrated at a non-toxic low dose, played a beneficial role in reducing lipogenesis caused by chronic ethanol feeding and these beneficial effects are obtained because of the specificity and reversibility of the proteasome inhibitor used.
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PMID:Proteasome inhibitor treatment reduced fatty acid, triacylglycerol and cholesterol synthesis. 2244 25

Methylglyoxal (MGO) is a major glycating agent that reacts with basic residues of proteins and promotes the formation of advanced glycation end products which are believed to play key roles in a number of pathologies, such as diabetes, Alzheimer's disease, and inflammation. We previously showed that MGO treatment targets the thioredoxin and the glyoxalase systems, leading to a decrease in Trx1 and Glo2 proteins in immortalized mouse hippocampal HT22 nerve cells. Here, we propose that autophagy is the underlying mechanism leading to Glo2 and Trx1 loss induced by MGO. The autophagic markers p62, and the lipidated and active form of LC3, were increased by MGO (0.5mM). Autophagy inhibition with bafilomycin or chloroquine prevented the decrease in Trx1 and Glo2 at 6 and 18h after MGO treatment. Proteasome inhibition by MG132 exacerbated the effect of MGO on Trx1 and Glo2 degradation (18h), further suggesting a role for autophagy. ATG5 small interfering RNA protected Trx1 and Glo2 from MGO-induced degradation, confirming Trx1 and Glo2 loss is mediated by autophagy. In the search for the signals that control autophagy, we found that AMPK activation, a known autophagy inducer, was markedly increased by MGO treatment. AMPK activation was confirmed by increased acetyl coenzyme A carboxylase phosphorylation, a direct AMPK substrate and by decreased mTOR phosphorylation, an indirect marker of AMPK activation. To confirm that MGO-mediated Trx1 and Glo2 degradation was AMPK-dependent, AMPK-deficient mouse embryonic fibroblasts (MEFs) were treated with MGO. Wildtype MEFs presented the expected decrease in Trx1 and Glo2, while MGO was ineffective in decreasing these proteins in AMPK-deficient cells. Overall, the data indicate that MGO activates autophagy in an AMPK-dependent manner, and that autophagy was responsible for Trx1 and Glo2 degradation, confirming that Trx1 and Glo2 are molecular targets of MGO.
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PMID:Methylglyoxal-induced AMPK activation leads to autophagic degradation of thioredoxin 1 and glyoxalase 2 in HT22 nerve cells. 2836 1