Musicki Biljana, Palese Michael A, Crone Julie K, Burnett Arthur L
Department of Urology, The Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
Biol Reprod. 2004 Feb;70(2):282-9. doi: 10.1095/biolreprod.103.021113. Epub 2003 Oct 1.
The objective of the present study was to evaluate whether vascular endothelial growth factor (VEGF)-induced penile erection is mediated by activation of endothelial nitric oxide synthase (eNOS) through its phosphorylation. We assessed the role of constitutively activated eNOS in VEGF-induced penile erection using wild-type (WT) and eNOS-knockout (eNOS(-/-)) mice with and without vasculogenic erectile dysfunction. Adult WT and eNOS(-/-) mice were subjected to sham operation or bilateral castration to induce vasculogenic erectile dysfunction. At the time of surgery, animals were injected intracavernosally with a replication-deficient adenovirus expressing human VEGF145 (10(9) particle units) or with empty virus (Ad.Null). After 7 days, erectile function was assessed in response to cavernous nerve electrical stimulation. Total and phosphorylated protein kinase B (Akt) as well as total and phosphorylated eNOS were quantitatively assessed in mice penes using Western immunoblot and immunohistochemistry. In intact WT mice, VEGF145 significantly increased erectile responses, and in WT mice after castration, it completely recovered penile erection. However, VEGF145 failed to increase erectile responses in intact eNOS(-/-) mice and only partially recovered erectile function in castrated eNOS(-/-) mice. In addition, VEGF145 significantly increased phosphorylation of eNOS at Serine 1177 by approximately 2-fold in penes of both intact and castrated WT mice. The data provide a molecular explanation for VEGF stimulatory effect on penile erection, which involves phosphorylated eNOS (Serine 1177) mediation.
本研究的目的是评估血管内皮生长因子（VEGF）诱导的阴茎勃起是否通过其磷酸化激活内皮型一氧化氮合酶（eNOS）介导。我们使用野生型（WT）和eNOS基因敲除（eNOS(-/-)）小鼠，在有或无血管性勃起功能障碍的情况下，评估组成型激活的eNOS在VEGF诱导的阴茎勃起中的作用。成年WT和eNOS(-/-)小鼠接受假手术或双侧去势以诱导血管性勃起功能障碍。在手术时，通过海绵体内注射表达人VEGF145的复制缺陷型腺病毒（10^9颗粒单位）或空病毒（Ad.Null）。7天后，评估对海绵体神经电刺激的勃起功能。使用蛋白质免疫印迹和免疫组织化学定量评估小鼠阴茎中总蛋白激酶B（Akt）和磷酸化蛋白激酶B以及总eNOS和磷酸化eNOS。在完整的WT小鼠中，VEGF145显著增加勃起反应，在去势后的WT小鼠中，它完全恢复了阴茎勃起。然而，VEGF145未能增加完整的eNOS(-/-)小鼠的勃起反应，并且仅部分恢复了去势的eNOS(-/-)小鼠的勃起功能。此外，VEGF145在完整和去势的WT小鼠阴茎中均使丝氨酸1177位点的eNOS磷酸化显著增加约2倍。这些数据为VEGF对阴茎勃起的刺激作用提供了分子解释，这涉及磷酸化eNOS（丝氨酸1177）介导。
