血管内皮细胞损伤是同型半胱氨酸(Hcy)致病的始动环节，RASAL1是下游通路的“分子开关”，而MAPK/MLC是体内磷酸化级联放大的重要通路，且DNA甲基化和转录因子异常是Hcy致病的重要机制，但Hcy是否通过RASAL1调控MAPK/MLC通路致肺血管内皮细胞(PMVEC)功能紊乱不清楚。因此拟采用共聚焦显微镜等观察RASAL1的变化并定位，确定其是Hcy引起PMVEC功能紊乱的重要基因；构建MAPK和MLC启动子区3’非编码序列载体共转染RASAL1-Luc报告基因，分别从RASAL1、MAPK和MLC等层面干预后，分析细胞凋亡、骨架蛋白等变化，阐明RASAL1调控MAPK/MLC通路在Hcy致PMVEC功能紊乱中的作用；从DNA甲基化和转录因子调控入手，探讨DNA甲基化和转录因子对靶基因的影响，揭示两者相互作用调控RASAL1引起PMVEC功能紊乱的机制，为防治Hcy提供实验依据。

Vascular endothelial cells injury is the initiating step of pathogenesis for homocysteine. RASAL1 is a key “molecular switch” for downstream signal pathway while MAPK/MLC is an important cascade amplification pathway for phosphorylation. Abnormal DNA methylation and transcription factor play crucial role in homocysteine-induced diseases. However, whether pulmonary vascular endothelial cells dysfunction-induced by homocysteine is regulated by RASAL1 via MAPK/MLC pathway remain unclear. In order to ascertain RASAL1 is the crucial gene for homocysteine-induced pulmonary vascular endothelial cells dysfunction, we will detect expression and location of RASA1 by confocal microscopy. Promoter non-coding sequence vector of MAPK and MLC will be constructed and co-transfected into RASAL1 luciferase reporter gene. Changes of cell apoptosis and cytoskeleton protein will be determined after RASAL1, MAPK and MLC intervening to clarify MAPK/MLC signal pathway regulated by RASAL1 is an important mechanism on homocysteine-induced pulmonary vascular endothelial cells dysfunction. DNA methylation and transcription factor regulation are used to explore its interaction on controlling expression and mechanism of RASAL1 in pulmonary vascular endothelial cells dysfunction and provide the experimental basis.