非对称性二甲基精氨酸通过Rho／ROCK信号通路介导大鼠血管平滑肌细胞迁移

目的探讨非对称性二甲基精氨酸（Asymmetric Dimethylarginine，ADMA）对血管平滑肌细胞（vascular smooth muscle cells，VSMCs）迁移和形态变化的影响，并探索Rho／ROCK和MAPK信号转导通路在其中的作用。方法原代培养大鼠VSMCs，并通过转染二甲基精氨酸二甲胺水解酶hDDAH2过表达载体，L-精氨酸（1mM）或ROCK抑制剂Y27632等预处理，观察细胞RhoA蛋白与底物rhotekin蛋白结合程度，ROCK底物MYPT-1磷酸化程度、VSMC迁移能力和细胞骨架及黏着斑定位情况。结果（1）ADMA诱导平滑肌细胞Rho/OCK信号转导通路；（2）Rho/OCK和ERK信号通路交联介导ADMA对平滑肌细胞迁移能力的诱导作用；（3）ADMA通过Rho/OCK诱导平滑肌细胞骨架无序排列、黏着斑定位改变；（4）L-精氨酸对上述变化有逆转作用。结论ADMA通过Rho/OCK和ERKl／2信号交联诱导VSMC迁移和表型转化，而L-精氨酸逆转ADMA引起的改变。

Asymmetric dimethylarginine induces Vascular Smooth Muscle Cells migration via the activation of Rho/ROCK signal pathway

Background Endogenous nitric oxide synthase (NOS) inhibitor,asymmetric dimethylarginine (ADMA) has been positively related to initiation and progression of atherosclerotic cardiovascular disease.Rho and Rho-kinase/ROCK mediate phenotypic change and migration of vascular smooth muscle cells (VSMCs).Here,we tested the hypothesis that ADMA induces VSMC migration and phenotypic change via the activation of Rho/ROCK pathway.Methods and Findings ADMA activated the Rho/ROCK signal pathway by elevating RhoA activity and by stimulating phosphorylation of a ROCK substrate,regulatory myosin phosphatase targeting subunit (MYPT)-1.The migrating ability was induced in VSMC,which suggested the phenotypic changes from a differentiated type to a dedifferentiated type induced by ADMA.Blocking the Rho/ROCK signal way with the ROCK inhibitor Y27632,and elimination of ADMA via overexpression of human dimethylarginine dimethylaminohydrolase 2 (hDDAH2) and the precursor of NO,L-arginine all attenuated ADMA pathological effects on VSMC phenotypic changes.Morphological detection showed disassembly of actin cytoskeleton and focal adhesions (FAs) induced by ADMA,which further verify the phenotypic changes from differentiation to dedifferentiation while can be blocked by Y27632 and L-arginine.Conclusions ADMA activates Rho/ROCK signal transduction pathway and leads to the migration of VSMCs.Our study may help to provide novel insights into the therapy and prevention of atherosclerosis.