NO-sGC-cGMP信号网络对血管内皮细胞和平滑肌细胞损伤的保护作用研究

Vascular endothelial cells and smooth muscle cells play an important role in the homeostasis of vascular structure and function, which is the important basis for the organism activities. NO-sGC-cGMP (nitric oxide-soluble guanylate cyclase acid-cyclic guanosine phosphate) signaling pathway is involved in the regulation of vascular endothelial cells and smooth muscle cells injury repair and self-equilibrium. However, its molecular mechanism is unclear. Our previous research showed that the activation of NO-sGC-cGMP signaling pathway can promote mitophagy in pulmonary artery smooth muscle cell and umbilical vein endothelial cell; NO-sGC-cGMP pathway can significantly promote cellular apoptosis via up-regulation of PAI-2 expression; NO-sGC-cGMP pathway can also promote the palmitoylation of smad7. Thus we hypothesize that NO-sGC-cGMP signaling pathway is involved in the regulation of vascular homeostasis by promoting the action of mitophagy, apoptosis and smad7 palmitoylation. In this study, we further analyze the molecular mechanism of NO-sGC-cGMP pathway in regulation mitophagy and smad7 palmitoylation at the cell and animal levels. Meanwhile, we would further identificate whether PAI-2 regulate the downstream TNFa pathway to promote apoptosis, and illuminate the effect and the balance of cell mitophagy, apoptosis and smad pathway in endothelial cells and smooth muscle cells during the process of vascular injury repair and vascular remodeling. In summary, we provide a new perspective to clarify the mechanism of NO-sGC-cGMP signaling pathway in regulation vascular injury repair and vascular remodeling. This work will contribute to the discovery of novel targeted agents, and provide new insights into the development of new approaches for chronic diseases therapy in elderly patients.

血管内皮细胞和平滑肌细胞在血管自稳态平衡中发挥重要作用。NO-sGC-cGMP（一氧化氮-可溶性鸟苷酸环化酶-环磷酸鸟苷）通路调控血管内皮细胞和平滑肌细胞损伤修复的机制尚不清楚。我们前期研究发现，NO-sGC-cGMP通路能促进肺动脉平滑肌细胞和脐静脉内皮细胞线粒体自噬的发生；调控PAI-2表达显著促进细胞凋亡；同时促进Smad7发生棕榈酰化修饰，据此提出假说：NO-sGC-cGMP通路通过促进线粒体自噬、凋亡和Smad7发生棕榈酰化修饰的作用参与血管损伤修复。本课题拟从细胞和动物水平进一步研究该通路促进线粒体自噬和Smad6/7棕榈酰化修饰发生的分子机制，分析下游靶基因PAI-2是否参与TNFa通路促进凋亡，阐明线粒体自噬、细胞凋亡和Smad6/7棕榈酰化修饰在内皮细胞和平滑肌细胞中的交互作用，从一个全新的角度阐明NO-sGC-cGMP信号通路调控血管损伤修复和血管重构的机制。

血管的正常形态和功能对维持循环系统和呼吸系统器官的正常功能至关重要。常见老年慢病如高血压、糖尿病有共同的病理生理特征，即血管损伤，并尤以血管内皮细胞和平滑肌细胞为甚。NO-sGC-cGMP（一氧化氮-可溶性鸟苷酸环化酶-环磷酸鸟苷）通路参与调控血管内皮细胞和平滑肌细胞的损伤修复，但其具体分子机制尚不清楚。我们前期研究发现，NO-sGC-cGMP通路能促进肺动脉平滑肌细胞和脐静脉内皮细胞线粒体自噬的发生；调控PAI-2表达显著促进细胞凋亡；同时促进Smad7发生棕榈酰化修饰，据此我们推测：NO-sGC-cGMP通路通过促进线粒体自噬、凋亡和Smad7发生棕榈酰化修饰的作用参与血管损伤修复。本课题在前期工作基础之上，发现NO-sGC-cGMP信号通路的激活能降低线粒体DNA拷贝数和膜电位，并通过调控线粒体自噬的发生从而影响细胞损伤修复与重构能力；NO-sGC-cGMP通过PAI-2-TNFa通路调控细胞凋亡参与血管损伤修复与重构；通过预测Smad6/7棕榈酰化修饰位点和棕榈酰转移酶，阐明NO-sGC-cGMP信号通路通过Smad6/7棕榈酰化修饰调控下游蛋白Smad2的磷酸化；发现cGMP负性调控LETM1的棕榈酰化从而抑制AKT通路活性；最后在动物模型试验中进一步验证NO-sGC-cGMP信号通路影响血管结构和功能。总之，本课题通过阐明线粒体自噬、细胞凋亡和Smad6/7棕榈酰化修饰在内皮细胞和平滑肌细胞中的交互作用，从一个全新的角度阐明NO-sGC-cGMP信号通路调控血管损伤修复和血管重构的机制。