5-Aminoimidazole-4-carboxyamide-ribonucleoside (AICAR)-Stimulated Hepatic Expression of Cyp4a10, Cyp4a14, Cyp4a31, and Other Peroxisome Proliferator-Activated Receptor α-Responsive Mouse Genes Is AICAR 5′-Monophosphate-Dependent and AMP-Activated Protein Kinase-Independent
5-Aminoimidazole-4-carboxyamide-ribonucleoside (AICAR)-Stimulated Hepatic Expression of Cyp4a10, Cyp4a14, Cyp4a31, and Other Peroxisome Proliferator-Activated Receptor α-Responsive Mouse Genes Is AICAR 5′-Monophosphate-Dependent and AMP-Activated Protein Kinase-Independent
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DOI：
10.1124/jpet.111.184242
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发表时间：
2011-12-01
影响因子：
3.5
通讯作者：
Johnson, Eric F.
中科院分区：
文献类型：
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作者：
Bumpus, Namandje N.;Johnson, Eric F.
AMPK的前体药物激活剂5-Aminoimidazole-4-carboxyamide-ribonucleoside使肝细胞色素P450 4a10、4a14和4a31mRNAs的表达分别增加2倍、3倍和4倍，肝微粒体月桂酸omega羟化增加2.8倍。同样，过氧化体增殖物激活受体α(PPARα)反应基因Acox1、Academy m、CPT1a和Fabp1的mRNA水平也因AICAR治疗而增加。AICAR没有在PPARα缺失小鼠中引起这些变化。在分离的小鼠肝细胞中，AICAR和腺苷产生类似的效应，这些反应可被PPARα拮抗剂[(2S)-2-[[(1Z)-1-methyl-3-oxo-3-[4-(trifluoromethyl)phenyl]-1-propenyl]amino]-3-[4-[2-(5-methyl-2-phenyl-4-oxazolyl)ethoxy]phenyl]propyl]-carbamic酸乙酯(GW6471)阻断。用化合物C(吗啡或6-[4-(2-piperidin-1-ylethoxy)phenyl]-3-pyridin-4-ylpyrazolo[1，5-a]pyrimidine))抑制AMPK不能阻断AICAR或腺苷对PPARα反应基因的诱导，而AMPK的非核苷类直接激活剂6，7-dihydro-4-hydroxy-3-(2‘-hydroxy[1，1’-biphenyl]-4-yl)-6-oxo-thieno[2，3-b]pyridine-5-carbonitrile(A-769662)不能增加PPARα反应基因的表达。腺苷激酶的抑制剂5-碘-结节杀菌素阻断了这些反应，提示AICAR和腺苷分别需要磷酸化为AICAR 5‘-单磷酸(ZMP)或AMP。PPARα激动剂油酸浓度升高和油酰辅酶A水平降低与PPARα依赖反应有关。ZMP和AMP对油酰辅酶A合成酶活性有抑制作用，IC50值分别为0.28和0.41 mM。这些结果表明，PPARα是由AICAR或腺苷治疗后ATP、AMP和ZMP水平改变导致的脂肪酸代谢受损引起的游离脂肪酸浓度增加而激活的。
5-Aminoimidazole-4-carboxyamide-ribonucleoside (AICAR), a prodrug activator of AMP-activated protein kinase (AMPK), increased hepatic expression of cytochrome P450 4a10, 4a14, and 4a31 mRNAs 2-, 3-, and 4-fold, respectively, and liver microsomal lauric acid omega-hydroxylation increased 2.8-fold. Likewise, mRNA levels of the peroxisome proliferator-activated receptor alpha (PPAR alpha)-responsive genes, Acox1, Acadm, Cpt1a, and Fabp1, were also increased by AICAR treatment. AICAR did not elicit these changes in PPAR alpha null mice. In isolated murine hepatocytes, AICAR and adenosine produced similar effects, and these responses were blocked by the PPAR alpha antagonist [(2S)-2-[[(1Z)-1-methyl-3-oxo-3-[4-(trifluoromethyl)phenyl]-1-propenyl]amino]-3-[4-[2-(5-methyl-2-phenyl-4-oxazolyl)ethoxy]phenyl]propyl]-carbamic acid ethyl ester (GW6471). Inhibition of AMPK using compound C (dorsomorphin or 6-[4-(2-piperidin-1-ylethoxy)phenyl]-3-pyridin-4-ylpyrazolo[1,5-a]pyrimidine) did not block the induction of the PPAR alpha-responsive genes by AICAR or adenosine, and 6,7-dihydro-4-hydroxy-3-(2'-hydroxy[1,1'-biphenyl]-4-yl)-6-oxo-thieno[2,3-b]pyridine-5-carbonitrile (A-769662), a non-nucleoside, direct activator of AMPK, did not increase expression of PPAR alpha-responsive genes. An inhibitor of adenosine kinase, 5-iodotubercidin, blocked these responses, suggesting that the phosphorylation of AICAR and adenosine to AICAR 5'-monophosphate (ZMP) or AMP, respectively, was required. Concentrations of ZMP and AMP were elevated and ATP levels diminished at 24 h. The PPAR alpha-dependent responses were associated with increased concentrations of oleic acid, a potent PPAR alpha agonist, and diminished levels of oleoyl-CoA. Oleoyl-CoA synthase activity was inhibited by ZMP and AMP with IC50 values of 0.28 and 0.41 mM, respectively. These results suggest that PPAR alpha is activated by increased concentrations of free fatty acids that may arise from impaired fatty acid metabolism caused by altered levels of ATP, AMP, and ZMP after AICAR or adenosine treatment.