SIRT1 在COPD患者外周血中EPCs减少中的作用及分子机制研究

The WHO predicts that COPD will become the fourth leading cause of death worldwide by 2030, cardiovascular diseases (CVD) were main factor in cause of death. The studies showed that the number decreased of EPCs in peripheral blood was important cause in high incidence of CVD. It was clarified that the number of EPCs in peripheral blood was reduced in COPD patients. SIRT1 played important role on proliferation,apoptosis and metabolism.If the expression of SIRT1 was decreased in cells, the transcription activity of activator protein-1 (AP-1) was increased,leading to up-regulation of cyclooxygenase-2 (COX-2) gene expression and increase cellular oxidative stress burden indirectly through deacetylation of FOXO3a.The reduced activity of SIRT1 resulted in an increase in apoptosis and reduce in proliferation. SIRT1 regulates physiological processes including apoptosis, cell differentiation, metabolism, and chronic inflammation, especially play important role on proliferation and apoptosis. However, whether SIRT1 played an important role on descreased number of EPCs in periphrial blood of COPD patients is unknown.The study aim is to explore the mechanism of SIRT1 effect on apoptosis and proliferation of EPCs in peripheral blood of COPD patients. We will observe if SIRT1 in EPCs affect expression of ROS level intracellular through immunofluorescence, transgenic, Westernblot and FACS.The expression of SIRT1 in EPCs were increased,the number of EPCs of COPD patients in periphrial blood were observed,and signal pathway involved were studied. Our aim is to find new target to decrease the incidence of CVD in COPD patients.

WHO预测到2030年，COPD跃居各种致死性疾病的第四位，心血管疾病是COPD主要死亡原因。COPD患者外周血中EPCs数量减少是造成心血管疾病高发的重要原因。SIRT1调节细胞分化、凋亡、代谢等过程。本研究团队前期研究中发现：COPD患者外周EPCsSIRT1表达明显减少。SIRT1表达降低，可增加AP-I转录，提高COX-2表达，增加细胞内氧化应激水平，促进细胞凋亡、抑制增殖。因此推测：SIRT1表达降低增加EPCs凋亡，抑制细胞增殖，造成细胞数量减少，通过相关通路影响EPCs功能。本课题拟采用免疫荧光、转基因、Westernblot及流式技术，研究SIRT1是否通过改变ROS在EPCs中的表达，影响COPD患者EPCs数量；通过转基因技术改善EPCs中SIRT1表达，观察SIRT1对COPD患者中EPCs数量的影响及相关信号通路参与，旨在为降低COPD患者心血管疾病提供治疗靶点。

慢性阻塞性肺病（chronic obstructive pulmonary disease，COPD）是心血管疾病（cardiovascular diseases,CVD）发生的独立危险因子，内皮祖细胞（Endothelial Progenitor Cells，EPCs）具有修复受损血管内皮的功能作用。我们前期实验研究发现COPD患者体内Sirt1的表达明显降低，且EPCs存在功能障碍及其在外周血数量明显减少。COPD大鼠EPCs内Sirt1表达量明显降低。体外研究表明:Sirt1 表达降低导致EPCs增殖、黏附、迁移能力降低，而EPCs凋亡增加，Sirt1表达增加可出现与之相反的结果。在EPCs中，Sirt1高表达时其下游基因FOXO3a表达增高，NF-κB及P53表达降低。在肺组织中，Sirt1高表达时其下游基因FOXO3a及P53表达增高，NF-κB表达降低。.Sirt1可以改善EPCs功能及降低其凋亡率，减少COPD所致CVD发生。Sirt1对EPCs功能的影响主要是通过Sirt1-FOXO3a/NF-κB/P53信号通路调控。