GPS2高甲基化调控的Ras/Raf/ERK轴在吸烟所致肺动脉重塑中的作用

Pulmonary hypertension associated with chronic obstructive pulmonary disease (PH-COPD) influences the quality of life and prognosis of COPD patients severely, in which smoking is one vital risk factor and ERK signal is relevant to its occurrence. Pre-study in our team has found that cigarette smoke led to GPS2 hypermethylation and the activation of Raf1 in rat pulmonary arteries. So we present a hypothesis that cigarette results in pulmonary arterial smooth muscle remodeling via GPS2 hypermethylation-induced activation of Ras/Raf1/ERK signal. We will regulate the expression of GPS2 by using adeno-associated virus for rats exposed to cigarette smoke, and examine the pulmonary arterial remodeling (PAR) and the expression of some related factors. In addition, we also apply gene transfer techniques and some signal inhibitors in primary human pulmonary arterial smooth muscle cells (HPASMCs), and explore the role of GPS2 hypermethylation- Ras/Raf1/ERK on cigarette-induced PAR. This study pays an attention to the important health issues. And it will elucidate the pathogenesis of PH-COPD in a new perspective, and provide the science base for prevention and treatment of PH-COPD.

慢阻肺相关肺动脉高压 (PH-COPD)严重影响了COPD病人的生活质量和预后，而吸烟是引起肺动脉平滑肌重塑的重要因素，其发生与ERK信号通路有关。课题组前期研究发现吸烟大鼠肺动脉GPS2启动子高甲基化和Raf1活化增强。在此基础上，提出吸烟通过GPS2高甲基化，活化Ras/Raf1/ERK信号通路，引起平滑肌重塑这一假说。本课题拟对香烟暴露大鼠，采用腺相关病毒调控GPS2水平，观察大鼠肺动脉重塑及相关因子表达情况；进而在香烟烟雾提取物（CSE）处理的平滑肌细胞上，采用基因转染技术和信号通路抑制剂调控GPS2下游相关信号分子（Ras-Raf1-ERK）的水平，验证GPS2甲基化-Ras/Raf1/ERK通路在吸烟所致肺动脉重塑的作用。课题针对危害国民的重大健康问题，从全新的角度阐明PH-COPD的发病机制，建立吸烟致肺动脉平滑肌重塑的路线图，为PH-COPD防治提供科学依据。

慢阻肺相关肺动脉高压 (PH-COPD)严重影响了COPD病人的生活质量和预后，而吸烟是引起肺动脉平滑肌重塑的重要因素，其发生与G蛋白信号-Raf1/ERK通路有关，而G蛋白抑制因子2（GPS2）在其作用尚不可知。课题组前期研究发现吸烟大鼠肺动脉GPS2启动子高甲基化和Raf1活化增强。在此基础上，提出吸烟通过GPS2高甲基化，活化Ras/Raf1/ERK信号通路，引起肺动脉平滑肌重塑这一假说。本课题通过对香烟暴露大鼠，采用腺相关病毒调控GPS2水平，观察大鼠肺动脉重塑及相关因子表达情况；进而在香烟烟雾提取物（CSE）处理的平滑肌细胞上，采用基因转染技术和信号通路抑制剂调控GPS2下游相关信号分子（RasRaf1-ERK）的水平，验证GPS2甲基化-Ras/Raf1/ERK通路在吸烟所致肺动脉重塑的作用。我们发现，不论体内、外，香烟均可减低肺动脉平滑肌中GPS2的表达；过表达GPS2可减轻香烟所致的大鼠PH与HPASMCs的增殖、迁移； ZOL（Ras抑制剂）可抑制GPS2si诱导的 Ras、Raf/ERK的活化及HPASMCs的增殖、迁移；而5-aza（DNA甲基化酶抑制剂）可抑制香烟诱导的HPASMCs中GPS2的下调。综上，DNA甲基化调控的GPS2在吸烟所致肺动脉重塑中发挥重要作用，从全新的角度阐明了PH-COPD的发病机制，有望为其防治提供其新的治疗靶点。