Methylarginines and Vascular Injury

本提案的长期目标是建立二甲基精氨酸二甲基氨基水解酶（DDAH）， 酶负责甲基精氨酸（MA）代谢，作为血管功能的关键调节剂， 对伤害的反应。改变的一氧化氮（NO）生物合成已被牵连的发病机制， 再狭窄损伤，并且似乎内源性一氧化氮合酶抑制剂ADMA的积累 和NMMA，是负责减少NO生成在这些条件下观察到的。我们已经表明 在兔和大鼠的球囊介导的再狭窄损伤模型中，血管DDAH的表达是 随着细胞MA水平的增加而显著降低。这个问题的总体假设 DDAH表达/活性的丧失导致MA积累和NO减少 生物可利用性，随后丧失了提供给 为了验证这一假设，我们将追求以下目标。在目标1中，我们将定义如何 DDAH的调节影响甲基精氨酸水平和随后的NOS衍生的NO和超氧化物 一代目标2.我们将确定DDAH在血管损伤中的调节及其在动脉损伤中的作用。 重塑这些研究将检测DDAH表达缺失对平滑肌细胞的影响， 增殖、迁移和内皮再生。此外，使用携带DDAH的AAV载体， 基因，我们将确定是否DDAH过度表达可以调节血管重塑过程， 改善血管功能。最终的目标是确定甲基精氨酸在动脉粥样硬化形成中的作用。因为 DDAH受LDL调节，我们将研究DDAH过表达对DDAH启动和 高脂血症状态下动脉粥样硬化的进展。我们相信，该项目将使DDAH成为 是血管对损伤反应的一个关键成分，可作为新的治疗靶点， 血管增生性疾病的治疗。

The long term objective of this proposal is to establish Dimethyarginie Dimethylaminohydrolase (DDAH), the enyme responsible for methylarginine (MA) metabolism, as a key regulator of vascular function and the response to injury. Altered nitric oxide (NO) biosynthesis has been implicated in the pathogenesis of restenosis injury and it appears that accumulation of the endogenous nitric oxide synthase inhibitors, ADMA and NMMA, are responsible for the reduced NO generation observed in these conditions. We have shown that in both rabbit and rat models of balloon- mediated restenosis injury, vascular DDAH expression is significantly decreased with a concomitant increase in cellular MA levels. The overall hypothesis of this proposal is that the loss of DDAH expression/activity results in MA accumulation and decreased NO bioavailabilty with subsequent loss of the anti-proliferative anti-atherogenic properties afforded to the vascular wall by NO. To test this hypotheis we will pursue the following aims. In aim 1, we will define how modulation of DDAH affects methylarginine levels and subsequent NOS-derived NO and superoxide generation. In aim 2. we will determine the modulation of DDAH in vascular injury and its role in arterial remodeling. These studies will examine the effects of loss of DDAH expression on smooth muscle cell proliferation, migration and endothelial regeneration. In addition, using and AAV vector carrying the DDAH gene, we will determine whether DDAH over expression can modulate the vascular remodelling process and improve vascular function. The final aim will determine the role methylarginines in atherogenesis. Because DDAH is regulated by LDL, we will study the effects of DDAH over expression on the initiation and progression of atherosclerosis in the hyperlipidemic state. We believe that this project will establish DDAH as a critical component in the vascular response to injury and may serve as a novel therapeutic target in the treatment of vasculoproliferative disorders.