细胞外游离微小核糖核酸206在低氧性肺血管重塑中的作用机制

The major pathological changes of hypoxic pulmonary hypertension (PH) are enhanced proliferation and migration, and suppressed apoptosis of pulmonary artery smooth muscle cells (PASMCs) under hypoxic environment, which leads to pulmonary vascular remodeling (PVR). The activation of HIF-1a/FHL-1 pathway is an early critical event in the PVR process. A negative relation between intracellular microRNA-206 (miR-206) and the activation of HIF-1a/FHL-1 pathway was discovered in our preliminary study, but the expression patterns of intracellular miR-206 and extracellular free miR-206 were different, the definite molecular mechanism of this phenomenon is not yet clear. This study is aimed to investigate the role of extracellular free miR-206 entering the cultured PASMCs, to identify the relationship between cell-free miR-206 with PVR in rat hypoxia-induced PH model, and to explore the relationship of cell-free miR-206 level with clinical and pathological parameters in PH patients, providing experimental basis for the new anti-PH treatment.

低氧性肺动脉高压（PH）的主要病理学改变是在低氧环境下，肺动脉平滑肌细胞（PASMCs）的增殖和迁移活性增强，凋亡抑制导致肺血管重塑（PVR）。HIF-1a/FHL-1通路的激活是PVR进程中的早期关键事件。申请者前期研究发现细胞内微小核糖核酸（microRNA）206与低氧环境下HIF-1a/FHL-1通路的激活有关，但细胞内miR-206和细胞外游离的miR-206表达模式不同，这一现象的分子机制尚不清楚。本研究拟通过细胞培养研究细胞外游离miR-206进入PASMCs及其作用机制；构建大鼠低氧诱导的PH模型研究细胞外游离miR-206水平改变与PVR的关系；通过研究PH患者细胞外游离miR-206的水平，探讨其与临床和病理指标的关系，为探索新的抗PH治疗提供实验依据。

低氧性肺动脉高压（pulmonary hypertension，PH）是一种以肺血管收缩和重塑（ vascular remodeling）为主要特征的严重疾病。在疾病早期，锌指核转录因子GATA结合蛋白6（GATA6）下调导致血管内皮细胞功能紊乱，促进肺微动脉平滑肌细胞（PASMC）增殖，在肺血管重塑中起关键作用。使用siRNA干扰技术，抑制GATA6的基因表达可上调缺氧诱导因子（hypoxia-inducible factor，HIF）活性。研究者早期工作发现微小核糖核酸206（microRNA-206）通过靶向HIF-1a/FHL-1通路参与低氧性PH的发生，而GATA6是否参与该调控通路并直接作用于PASMC尚不清楚。本研究成功构建CRISPR/Cas9介导的基因沉默体系，靶向敲除GATA6 DNA。研究在低氧环境中，GATA6是否为miR-206/HIF-1a轴的下游关键基因，通过作用于PASMC早期诱发并推动PH的发生发展，为探索新的抗 PH 治疗提供重要实验依据。