A key role for tetrahydrobiopterin-dependent endothelial NOS regulation in resistance arteries: studies in endothelial cell tetrahydrobiopterin-deficient mice.
A key role for tetrahydrobiopterin-dependent endothelial NOS regulation in resistance arteries: studies in endothelial cell tetrahydrobiopterin-deficient mice.
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DOI：
10.1111/bph.13728
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发表时间：
2017-04
影响因子：
7.3
通讯作者：
Douglas G
中科院分区：
文献类型：
--
作者：
Chuaiphichai S;Crabtree MJ;Mcneill E;Hale AB;Trelfa L;Channon KM;Douglas G
辅因子四氢生物蝶呤(BH4)是血管生理学中内皮型一氧化氮合酶(ENOS)功能及其衍生的NO和ROS信号的重要调节因子。为了确定新生内皮细胞BH4合成对阻力动脉血管运动功能的生理需求，我们建立了内皮细胞特异性缺失Gch1的小鼠模型，编码BH4生物合成的关键酶GTP环水解酶1(GTPCH)，并评价了BH4依赖的eNOS调节、eNOS来源的NO和ROS的产生。线状肌图法测定小鼠肠系膜二级动脉的反应性。采用高效液相色谱法测定BH4、BH2和生物蝶呤。Western blotting进行基因表达分析。Gch1fl/flTie2cre小鼠肠系膜动脉GTPCH蛋白和BH4水平降低。内皮细胞BH4缺陷导致Gch1 fl/flTie2cre小鼠肠系膜动脉eNOS解偶联，ROS产生增加，NO产生减少。Gch1fl/flTie2cre增强肠系膜动脉对U46619和苯肾上腺素的收缩作用，这一作用可被L所阻断。与野生型仔鼠相比，Gch1 fl/flTie2cre小鼠肠系膜动脉对ACh和SLIGRL的内皮依赖性血管扩张功能受损。在Gch1fl/flTie2cre的肠系膜动脉中，eNOS衍生的NO介导的血管扩张功能的丧失与eNOS衍生的过氧化氢和环氧合酶衍生的血管扩张剂的增加有关。内皮细胞Gch1和BH4依赖的eNOS调节在维持阻力动脉的血管内稳态中起着关键作用。因此，靶向血管Gch1和BH4的生物合成可能为心血管疾病患者微血管功能障碍的防治提供新的治疗靶点。
The cofactor tetrahydrobiopterin (BH4) is a critical regulator of endothelial NOS (eNOS) function, eNOS‐derived NO and ROS signalling in vascular physiology. To determine the physiological requirement for de novo endothelial cell BH4 synthesis for the vasomotor function of resistance arteries, we have generated a mouse model with endothelial cell‐specific deletion of Gch1, encoding GTP cyclohydrolase 1 (GTPCH), an essential enzyme for BH4 biosynthesis, and evaluated BH4‐dependent eNOS regulation, eNOS‐derived NO and ROS generation. The reactivity of mouse second‐order mesenteric arteries was assessed by wire myography. High performance liquid chromatography was used to determine BH4, BH2 and biopterin. Western blotting was used for expression analysis. Gch1 fl/flTie2cre mice demonstrated reduced GTPCH protein and BH4 levels in mesenteric arteries. Deficiency in endothelial cell BH4 leads to eNOS uncoupling, increased ROS production and loss of NO generation in mesenteric arteries of Gch1 fl/flTie2cre mice. Gch1 fl/flTie2cre mesenteric arteries had enhanced vasoconstriction to U46619 and phenylephrine, which was abolished by L‐NAME. Endothelium‐dependent vasodilatations to ACh and SLIGRL were impaired in mesenteric arteries from Gch1 fl/flTie2cre mice, compared with those from wild‐type littermates. Loss of eNOS‐derived NO‐mediated vasodilatation was associated with increased eNOS‐derived H2O2 and cyclooxygenase‐derived vasodilator in Gch1 fl/flTie2cre mesenteric arteries. Endothelial cell Gch1 and BH4‐dependent eNOS regulation play pivotal roles in maintaining vascular homeostasis in resistance arteries. Therefore, targeting vascular Gch1 and BH4 biosynthesis may provide a novel therapeutic target for the prevention and treatment of microvascular dysfunction in patients with cardiovascular disease.