RhoA/Rho-kinase suppresses endothelial nitric oxide synthase in the penis: A mechanism for diabetes-associated erectile dysfunction
RhoA/Rho-kinase suppresses endothelial nitric oxide synthase in the penis: A mechanism for diabetes-associated erectile dysfunction
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DOI：
10.1073/pnas.0400520101
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发表时间：
2004-06-15
影响因子：
11.1
通讯作者：
Kadowitz, PJ
中科院分区：
文献类型：
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作者：
Bivalacqua, TJ;Champion, HC;Kadowitz, PJ
糖尿病海绵体中存在内皮源性一氧化氮的显着损伤。 RhoA/Rho 激酶可能抑制内皮一氧化氮合酶 (eNOS)。在这里，我们测试了 RhoA/Rho 激酶导致糖尿病相关勃起功能障碍和链脲佐菌素 (STZ) 糖尿病大鼠阴茎中 eNOS 下调的假设。 Rhokinase 和 eNOS 蛋白共定位于海绵体的内皮细胞中。 STZ 糖尿病大鼠阴茎中 RhoA/Rho 激酶蛋白丰度和 MYPT-1 Thr-696 磷酸化水平升高。此外，STZ 糖尿病阴茎中的 eNOS 蛋白表达、海绵体组成型 NOS 活性和 cGMP 水平均降低。为了评估 RhoA/Rho 激酶在阴茎中的功能作用，我们评估了编码显性失活 RhoA 突变体 (AAVTCMV19NRhoA) 的腺相关病毒对 STZ 糖尿病大鼠体内 RhoA/Rho 激酶和 eNOS 以及勃起功能的影响。当海绵体 eNOS 蛋白、组成型 NOS 活性和 cGMP 水平恢复到对照大鼠的水平时，转染 AAVCMVT19NRhoA 的 STZ 糖尿病大鼠的 RhoA/Rhokinase 和 MYPT-1 磷酸化降低。 STZ 糖尿病大鼠对海绵体神经刺激的勃起反应显着降低。 AAVT19NRhoA 基因转移将 STZ 糖尿病大鼠的勃起反应改善至与对照相似的值。这些数据证明了糖尿病中阴茎 eNOS 下调的机制，该机制是通过激活 RhoA/Rho 激酶途径介导的，这一机制以前未曾描述过。重要的是，这些数据表明抑制 RhoA/Rho 激酶可提高 eNOS 蛋白含量和活性，从而恢复糖尿病患者的勃起功能。
Significant impairment in endothelial-derived nitric oxide is present in the diabetic corpus cavernosum. RhoA/Rho-kinase may suppress endothelial nitric oxide synthase (eNOS). Here, we tested the hypothesis that RhoA/Rho-kinase contributes to diabetes-related erectile dysfunction and down-regulation of eNOS in the streptozotocin (STZ)-diabetic rat penis. Colocalization of Rhokinase and eNOS protein was present in the endothelium of the corpus cavemosum. RhoA/Rho-kinase protein abundance and MYPT-1 phosphorylation at Thr-696 were elevated in the STZ-diabetic rat penis. In addition, eNOS protein expression, cavernosal constitutive NOS activity, and cGMP levels were reduced in the STZ-diabetic penis. To assess the functional role of RhoA/Rhokinase in the penis, we evaluated the effects of an adeno-associated virus encoding the dominant-negative RhoA mutant (AAVTCMV19NRhoA) on RhoA/Rho-kinase and eNOS and erectile function in vivo in the STZ-diabetic rat. STZ-diabetic rats transfected with AAVCMVT19NRhoA had a reduction in RhoA/Rhokinase and MYPT-1 phosphorylation at a time when cavernosal eNOS protein, constitutive NOS activity, and cGMP levels were restored to levels found in the control rats. There was a significant decrease in erectile response to cavernosal nerve stimulation in the STZ-diabetic rat. AAVT19NRhoA gene transfer improved erectile responses in the STZ-diabetic rat to values similar to control. These data demonstrate a previously undescribed mechanism for the down-regulation of penile eNOS in diabetes mediated by activation of the RhoA/Rho-kinase pathway. Importantly, these data imply that inhibition of RhoA/Rho-kinase improves eNOS protein content and activity thus restoring erectile function in diabetes.