Department of Health and Kinesiology, Texas A&M University, MS 4243, College Station, TX, 77843-4243, USA.
Eur J Appl Physiol. 2013 Nov;113(11):2761-8. doi: 10.1007/s00421-013-2715-7. Epub 2013 Aug 31.
We tested the hypothesis that impaired endothelium-dependent relaxation in aged aorta is due, in part, to altered protein:protein interactions between endothelial nitric oxide synthase (eNOS) and key regulatory proteins resulting in impaired nitric oxide (NO)-mediated relaxation. We also hypothesized that endurance exercise training improves or restores NO-mediated vasorelaxation in aged aorta by reversing the detrimental effects of aging on protein:protein interaction between eNOS and its key regulatory proteins.
Young (2 month) and old (22 month) rats were exercise trained (Ex) or remained sedentary (Sed) for 10 weeks yielding four groups of rats: (1) young Sed, (2) young Ex, (3) old Sed, and (4) old Ex. Endothelium-dependent relaxation to acetylcholine (ACh) and protein:protein interactions were assessed in aortas. To determine the role of eNOS, endothelium-dependent relaxation to ACh was assessed in the presence of L-NAME. Protein:protein interactions were assessed using co-immunoprecipitation.
Acetylcholine-induced relaxation was impaired in OldSed relative to YoungSed aortas. Training restored ACh-induced vasorelaxation responses so that OldEx were not different from YoungSed. L-NAME abolished the effects of age and exercise training on ACh-induced relaxation responses. Aging resulted in lower Cav1:eNOS and CaM:eNOS interactions but had no effect on Hsp90:eNOS interaction. Exercise training did not alter protein:protein interactions.
Nitric oxide-mediated, endothelium-dependent relaxation is impaired in old aorta, which is associated with reduced Cav1:eNOS and CaM:eNOS interactions. Exercise training restores endothelium-dependent relaxation in old aortas by enhancing NO-mediated vasorelaxation. The beneficial effect of training is not mediated by reversing the detrimental effects of aging on protein:protein interactions between eNOS and its key regulatory proteins.
我们验证了一个假说，即老年主动脉内皮依赖性舒张功能障碍部分是由于内皮型一氧化氮合酶（eNOS）与其关键调节蛋白之间的蛋白-蛋白相互作用改变，导致一氧化氮（NO）介导的舒张功能受损。我们还假设，耐力运动训练通过逆转衰老对 eNOS 与其关键调节蛋白之间的蛋白-蛋白相互作用的不利影响，改善或恢复老年主动脉的 NO 介导的血管舒张作用。
将年轻（2 个月）和老年（22 个月）大鼠分别进行运动训练（Ex）或保持安静（Sed）10 周，得到 4 组大鼠：（1）年轻 Sed，（2）年轻 Ex，（3）老年 Sed，和（4）老年 Ex。乙酰胆碱（ACh）诱导的舒张反应和蛋白-蛋白相互作用在主动脉中进行评估。为了确定 eNOS 的作用，在存在 L-NAME 的情况下评估 ACh 诱导的内皮依赖性舒张反应。使用共免疫沉淀评估蛋白-蛋白相互作用。
与年轻 Sed 主动脉相比，OldSed 主动脉中 ACh 诱导的舒张反应受损。训练恢复了 ACh 诱导的血管舒张反应，使 OldEx 与 YoungSed 无差异。L-NAME 消除了年龄和运动训练对 ACh 诱导的舒张反应的影响。衰老导致 Cav1:eNOS 和 CaM:eNOS 相互作用降低，但对 Hsp90:eNOS 相互作用没有影响。运动训练没有改变蛋白-蛋白相互作用。
NO 介导的内皮依赖性舒张在老年主动脉中受损，这与 Cav1:eNOS 和 CaM:eNOS 相互作用降低有关。运动训练通过增强 NO 介导的血管舒张作用来恢复老年主动脉的内皮依赖性舒张。训练的有益效果不是通过逆转衰老对 eNOS 与其关键调节蛋白之间的蛋白-蛋白相互作用的不利影响来介导的。
