Isoform-specific regulation by NG, NG-dimethylarginine dimethylaminohydrolase of rat serum asymmetric dimethylarginine and vascular endothelium-derived relaxing factor/NO
Isoform-specific regulation by NG, NG-dimethylarginine dimethylaminohydrolase of rat serum asymmetric dimethylarginine and vascular endothelium-derived relaxing factor/NO
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DOI：
10.1161/circresaha.107.158915
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发表时间：
2007-09-14
影响因子：
20.1
通讯作者：
Wilcox, Christopher S.
中科院分区：
文献类型：
--
作者：
Wang, Dan;Gill, Pritmohinder S.;Wilcox, Christopher S.
抑制NO合酶的不对称二甲基精氨酸（ADMA）被N-G，N-G-二甲基精氨酸二甲氨基水解酶（DDAH）灭活。我们测试了DDAH-1或-2是否调节血清ADMA（S-ADMA）和/或内皮源性舒张因子（EDRF）/NO。向大鼠静脉内给予靶向DDAH-1或-2的小抑制性（si）RNA或siRNA对照。72小时后，从乙酰胆碱诱导的、NO脱氢酶依赖性舒张和4-氨基-5-甲氨基-2 '，7'-二氟荧光素二乙酸酯评估EDRF/NO在分离的肠系膜阻力血管（MRV）中的NO活性。DDAH-1和DDAH-2的mRNA表达在肾皮质和肝脏中分别高2倍和7倍，而DDAH-2和DDAH-1的表达在MRV中高5倍。在相应的siRNA后72小时，DDAH-1或-2的蛋白质和mRNA在肾皮质、肝脏和MRV中选择性地减少35%至85%。SADMA仅在siDDAH-1后增加（266 +/- 25 vs 342 +/- 39 [mean +/- SD] nmol center dot L-1; P < 0.005），而EDRF/NO反应和NO活性在siDDAH-1后没有一致的变化，但在siDDAH-2后大大降低。任何siRNA均未显著改变平均动脉压。总之，SADMA受DDAH-1调节，DDAH-1在肾皮质和肝脏中的ADMA代谢位点表达，而EDRF/NO主要受DDAH-2调节，DDAH-2在血管中强烈表达。这意味着DDAH同种型的特定功能。
Asymmetric dimethylarginine (ADMA), which inhibits NO synthase, is inactivated by N-G,N-G-dimethylarginine dimethylaminohydrolase (DDAH). We tested whether DDAH-1 or -2 regulates serum ADMA (S-ADMA) and/or endothelium-derived relaxing factor (EDRF)/NO. Small inhibitory (si)RNAs targeting DDAH-1 or -2, or an siRNA control were given intravenously to rats. After 72 hours, EDRF/NO was assessed from acetylcholine-induced, NO synthase-dependent relaxation and 4-amino-5-methylamino-2',7'-diflouroflourescein diacetate for NO activity in isolated mesenteric resistance vessels (MRVs). Expression of mRNA for DDAH-1 versus -2 was 2- and 7-fold higher in the kidney cortex and liver, respectively, whereas expression of DDAH-2 versus -1 was 5-fold higher in MRVs. The proteins and mRNAs for DDAH-1 or -2 were reduced selectively by 35% to 85% in the kidney cortex, liver, and MRVs 72 hours following the corresponding siRNA. SADMA was increased only after siDDAH-1 (266 +/- 25 versus 342 +/- 39 [mean +/- SD] nmol center dot L-1; P < 0.005), whereas EDRF/NO responses and NO activity were not changed consistently by siDDAH-1 but were greatly reduced after siDDAH-2. Mean arterial pressure was not changed significantly by any siRNA. In conclusion, SADMA is regulated by DDAH-1, which is expressed at sites of ADMA metabolism in the kidney cortex and liver, whereas EDRF/NO is regulated primarily by DDAH-2, which is expressed strongly in blood vessels. This implies specific functions of DDAH isoforms.