From the Cardiovascular Research Center (Q.L., D.A., S.K., J.E., A.W., P.L.H.) and Neuroprotection Research Laboratory (E.M., K.H., E.H.L.), Massachusetts General Hospital and Harvard Medical School, Boston, MA; the Departments of Anesthesiology and Molecular, Pharmacology, and Experimental Therapeutics, Mayo Clinic, Rochester, MN (L.V.U., Z.K.); and the Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT (W.S.).
Stroke. 2013 Nov;44(11):3183-8. doi: 10.1161/STROKEAHA.113.002073. Epub 2013 Aug 29.
Phosphorylation of eNOS, an important post-translational modulator of its enzymatic activity, is reduced in diabetes mellitus. We hypothesized that modulation of eNOS phosphorylation could overcome diabetic vascular dysfunction and improves the outcome to stroke.
We used the db/db mouse model of type 2 diabetes mellitus. We mated db/db mice with eNOS knock-in mice that carry single amino acid mutations at the S1176 phosphorylation site; the phosphomimetic SD mutation (serine replaced by aspartate) shows increased eNOS enzymatic activity, whereas the unphosphorylatable SA mutation (serine replaced by alanine) shows decreased eNOS activity. We characterized the vascular anatomy, baseline physiological parameters, and vascular reactivity. We used the middle cerebral artery occlusion model of stroke and measured infarct volume and neurological deficits.
db/db mice showed diminished eNOS phosphorylation at S1176. eNOS SD and SA mutations do not change the vascular anatomy at the Circle of Willis, brain capillary density, heart rate, or arterial blood gases of db/db mice. The eNOS SD mutation, but not the SA mutation, lowers blood pressure and improves vascular reactivity to acetylcholine in db/db mice. The eNOS SD mutation reduces stroke size and neurological deficit after middle cerebral artery occlusion.
Diminished eNOS phosphorylation is a mechanism of vascular dysfunction in db/db mice. We show here that modulation of the eNOS S1176 phosphorylation site in db/db mice is associated with improved vascular reactivity and improved outcome to stroke after middle cerebral artery occlusion.
磷酸化 eNOS（一种重要的酶活性翻译后修饰物）在糖尿病中减少。我们假设调节 eNOS 磷酸化可以克服糖尿病血管功能障碍，并改善中风的预后。
我们使用了 2 型糖尿病 db/db 小鼠模型。我们将 db/db 小鼠与携带 S1176 磷酸化位点单氨基酸突变的 eNOS 敲入小鼠交配；磷酸化模拟 SD 突变（丝氨酸被天冬氨酸取代）显示出增加的 eNOS 酶活性，而不可磷酸化的 SA 突变（丝氨酸被丙氨酸取代）显示出降低的 eNOS 活性。我们对血管解剖结构、基础生理参数和血管反应性进行了特征描述。我们使用了大脑中动脉闭塞的中风模型，并测量了梗死体积和神经功能缺损。
db/db 小鼠的 eNOS 在 S1176 处的磷酸化减少。eNOS SD 和 SA 突变不会改变 db/db 小鼠的 Willis 环血管解剖结构、脑毛细血管密度、心率或动脉血气。eNOS SD 突变而不是 SA 突变可降低 db/db 小鼠的血压并改善乙酰胆碱引起的血管反应性。eNOS SD 突变可减少大脑中动脉闭塞后的中风面积和神经功能缺损。
eNOS 磷酸化减少是 db/db 小鼠血管功能障碍的一种机制。我们在这里表明，db/db 小鼠中 eNOS S1176 磷酸化位点的调节与改善血管反应性和改善大脑中动脉闭塞后的中风预后有关。
