Kavoussi Parviz K, Smith Ryan P, Oliver Janine L, Costabile Raymond A, Steers William D, Brown-Steinke Katie, de Ronde Kimberly, Lysiak Jeffrey J, Palmer Lisa A
Department of Urology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.
Int J Impot Res. 2019 Jan;31(1):31-38. doi: 10.1038/s41443-018-0056-0. Epub 2018 Aug 20.
Neuronal and endothelial nitric oxide synthases (nNOS and eNOS respectively) play major roles in generating the nitric oxide bioactivity necessary for erectile function. S-nitrosylation has been shown to regulate NOS activity. The presence of S-nitrosylated NOS in the penis and the impact of NOS S-nitrosylation/denitrosylation on erectile function were examined. S-nitrosylated forms of NOS were identified by biotin-switch assay followed by western blot analysis. Erectile function in S-nitrosoglutathione reductase deficient (GSNO) and null (GSNO) mice were assessed by continuous cavernous nerve electrical stimulation (CCNES). Glutathione ethyl ester (GSHee) was used to manipulate S-nitrosylated NOS levels. Immunohistological and immunofluorescence analyses were used to identify the location of eNOS and GSNO-R in corporal tissue. eNOS and nNOS were S-nitrosylated in unstimulated penises of the mice. CCNES resulted in a time-dependent increase in eNOS S-nitrosylation with peak eNOS S-nitrosylation observed during detumescence. S-nitrosylated nNOS levels were unchanged. Intracorporal injection of GSHee reduced S-nitrosylated eNOS levels, enhancing time to maximum intracorporal pressure (ICP). eNOS and GSNO-R co-localize to the endothelium of the corpus cavernosum in the mouse and the human. ICP measurements obtained during CCNES demonstrate GSNO-R and GSNO-R animals cannot maintain an elevated ICP. Results suggest eNOS S-nitrosylation/denitrosylation is an important mechanism regulating eNOS activity during erectile function. GSNO-R is a key enzyme involved in the eNOS denitrosylation. The increase in eNOS S-nitrosylation (inactivation) observed with tumescence may begin a cycle leading to detumescence. Clinically this may indicate that alterations in the balance of S-nitrosylation/denitrosylation either directly or indirectly contribute to erectile dysfunction.
神经元型和内皮型一氧化氮合酶（分别为nNOS和eNOS）在产生勃起功能所需的一氧化氮生物活性方面发挥着主要作用。已证明S-亚硝基化可调节一氧化氮合酶的活性。研究了阴茎中S-亚硝基化一氧化氮合酶的存在情况以及一氧化氮合酶的S-亚硝基化/去亚硝基化对勃起功能的影响。通过生物素转换法，随后进行蛋白质印迹分析来鉴定一氧化氮合酶的S-亚硝基化形式。通过持续海绵体神经电刺激（CCNES）评估S-亚硝基谷胱甘肽还原酶缺陷（GSNO）和缺失（GSNO）小鼠的勃起功能。使用谷胱甘肽乙酯（GSHee）来调控S-亚硝基化一氧化氮合酶的水平。采用免疫组织学和免疫荧光分析来确定eNOS和GSNO-R在海绵体组织中的位置。在未受刺激的小鼠阴茎中，eNOS和nNOS发生了S-亚硝基化。CCNES导致eNOS的S-亚硝基化呈时间依赖性增加，在消肿过程中观察到eNOS的S-亚硝基化达到峰值。S-亚硝基化nNOS的水平未发生变化。海绵体内注射GSHee可降低S-亚硝基化eNOS的水平，延长达到最大海绵体内压（ICP）的时间。在小鼠和人类中，eNOS和GSNO-R共定位于海绵体的内皮细胞。在CCNES期间获得的ICP测量结果表明，GSNO-R和GSNO-R动物无法维持升高的ICP。结果表明，eNOS的S-亚硝基化/去亚硝基化是勃起功能过程中调节eNOS活性的重要机制。GSNO-R是参与eNOS去亚硝基化的关键酶。勃起时观察到的eNOS的S-亚硝基化（失活）增加可能会引发一个导致消肿勃起功能障碍。临床上，这可能表明S-亚硝基化/去亚硝基化平衡的改变直接或间接导致勃起功能障碍。
