eNOS Regulatory Mechanisms in Penile Vascular Function

描述(申请人提供)：最近发表的研究支持了一个新兴的概念，即血管和血窦内皮细胞，特别是定位于这种细胞结构的内皮型一氧化氮合酶(ENOS)在阴茎的血管内稳态和勃起生理方面发挥着重要作用。对阴茎eNOS的研究表明，在血流刺激下，该酶被特定的磷酸化机制激活，从而稳定、连续地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重要作用，调节勃起反应的勃起和勃起维持阶段。进一步的研究发现，在各种与勃起功能障碍相关的情况下，eNOS在阴茎中缺乏，包括糖尿病和衰老。这些报告与流行病学研究相一致，这些研究发现，在患有心血管疾病的人中，勃起功能障碍的发生率很高，这导致了一种常见的致病联系：内皮功能障碍。然而，与血管性勃起功能障碍相关的阴茎内皮功能缺陷的确切机制仍然知之甚少。据推测，eNOS在各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了影响。因此，这项研究计划集中在两个领域，研究几种特定的分子机制控制eNOS在阴茎中的作用与该器官的生理和病理生理事件相关，以及评估“激活的”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)研究大鼠生理性勃起和勃起过程中阴茎eNOS亚型特异性调控机制(即翻译后磷酸化、蛋白质-蛋白质相互作用)；(2)利用猪和啮齿动物模型，确定eNOS亚型特异性调控机制在动脉粥样硬化相关性勃起功能障碍发病机制中的作用；(3)确定eNOS亚型特异性调控机制在年龄相关性勃起功能障碍大鼠发病机制中的作用；以及(4)在血管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“激活的”eNOS作为改善勃起功能的分子靶点。这项工作可能不仅会推进勃起功能障碍的治疗，而且还可能推进一般的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.