eNOS Regulatory Mechanisms in Penile Vascular Function

描述（由申请人提供）：最近发表的研究支持了一个新兴的概念，即血管和窦内皮，特别是内皮型一氧化氮合酶（eNOS），定位于这种细胞结构，在血管稳态和阴茎勃起生理方面发挥重要作用。对阴茎eNOS的研究表明，该酶在血流刺激下被特定的磷酸化机制激活，从而以稳定、连续的方式释放气态信使分子一氧化氮（NO）。这一发现表明，eNOS在no介导的阴茎勃起中起着重要作用，调节勃起反应的阴茎肿胀和勃起维持阶段。进一步的研究表明，在包括糖尿病和衰老在内的与勃起功能障碍相关的各种情况下，阴茎中eNOS缺乏。这些报告与流行病学研究一致，发现心血管疾病患者勃起功能障碍发生率高，从而提出了一个共同的致病联系：内皮功能障碍。然而，阴茎内皮功能缺陷与血管源性勃起功能障碍的确切机制尚不清楚。假设eNOS在多种复杂调控机制的控制下在阴茎中的作用对该器官的内皮依赖性生物学功能产生影响。因此，本研究计划主要围绕两个方面展开，一是研究eNOS在阴茎中与生理和病理生理事件相关的控制eNOS作用的几个特定分子机制，二是评估“活化”的eNOS作为维持阴茎血管功能的血管保护分子靶点。具体目的是：(1)表征eNOS亚型特异性调控机制（即翻译后磷酸化、蛋白-蛋白相互作用）在大鼠阴茎生理性阴茎松弛和勃起过程中的作用；(2)通过猪和啮齿动物模型，确定eNOS在阴茎中异构体特异性调控机制在动脉粥样硬化相关勃起功能障碍发病机制中的作用；(3)确定eNOS在阴茎中异构体特异性调控机制在大鼠年龄相关性勃起功能障碍发病中的作用；(4)在血管源性勃起功能障碍的啮齿动物模型中，通过选择干预措施（即生长因子治疗、药物诱导和基因转移），评估“活化”eNOS作为改善勃起功能的分子靶点。这项工作不仅可以促进勃起功能障碍的治疗，还可以促进内皮功能障碍的治疗。

DESCRIPTION (provided by applicant): Recently published work has supported the emerging concept that the vascular and sinusoidal endothelium and, specifically, endothelial nitric oxide synthase (eNOS) localized to this cellular structure play important roles in aspects of the vascular homeostasis and erection physiology of the penis. Investigations of eNOS in the penis have shown that the enzyme is activated by a specific phosphorylation mechanism under blood flow stimulation so that it releases the gaseous messenger molecule nitric oxide (NO) in a steady, continuous manner. This finding indicates that eNOS contributes significantly to NO-mediated penile erection, regulating the penile tumescence and erection maintenance phases of the erectile response. Further investigation has revealed that eNOS is deficient in the penis under various conditions associated with erectile dysfunction including diabetes and aging. These reports correspond with epidemiologic studies that have identified high rates of erectile dysfunction in individuals with cardiovascular diseases, leading to suggestions of a common pathogenic link: endothelial dysfunction. However, the precise mechanisms underlying the putatively defective endothelial function in the penis associated with vasculogenic erectile dysfunction remain poorly understood. It is hypothesized that the actions of eNOS in the penis under the control of various complex regulatory mechanisms have an impact on the endothelial-dependent biological functions of this organ. Accordingly, this research proposal centers on two areas, the investigation of several specific molecular mechanisms controlling eNOS actions in the penis in correlation with physiologic and pathophysiologic events of this organ, and the assessment of "activated" eNOS as a vasculoprotective molecular target for preserving penile vascular function. Specific aims are: (1) to characterize eNOS isoform-specific regulatory mechanisms (i.e., post-translational phosphorylation, protein-protein interactions) operating in the penis during physiologic penile flaccidity and erection in the rat; (2) to determine roles of eNOS isoform-specific regulatory mechanisms in the penis in the pathogenesis of atherosclerosis-associated erectile dysfunction using porcine and rodent animal models; (3) to determine roles of eNOS isoform-specific regulatory mechanisms in the penis in the pathogenesis of age-associated erectile dysfunction in the rat; and (4) to evaluate "activated" eNOS as a molecular target for improving erectile function using select interventions (i.e., growth factor therapy, pharmacoinduction, and gene transfer) in rodent animal models of vasculogenic erectile dysfunction. The work may advance treatments not only for erectile dysfunction, but also for disorders of endothelial dysfunction in general.