Calcineurin/NFAT信号通路上调5型磷酸二酯酶的表达及介导内皮素-1诱导的肺动脉平滑肌细胞增殖

Calcineurin/NFAT signaling pathway mediates endothelin-1-induced pulmonary artery smooth muscle cell proliferation by regulating phosphodiesterase-5

目的探讨Calcineurin/NFAT信号通路是否介导内皮素-1(ET-1)诱导的5型磷酸二酯酶(PDE5)的表达及肺动脉平滑肌细胞(PASMCs)的增殖;同时验证Calcineurin抑制剂环孢素A及PDE5抑制剂西地那非能否抑制ET-1刺激的PASMCs增殖。方法以ET-1刺激PASMCs增殖,分别于ET-1刺激前给予环孢素A或西地那非抑制Calcineurin或PDE5的活性。采用Calcineurin活性检测试剂盒检测其活性,免疫印迹法检测PDE5的表达,酶联免疫吸附法检测cGMP的含量,3H-TdR渗入法检测PASMCs的增殖。结果 ET-1可激活原代培养的PASMCs中Calcineurin的活性,上调PDE5表达,降低cGMP的水平。Calcineurin特异性抑制剂环孢素A可阻断ET-1的上述作用;抑制PDE5的活性可逆转ET-1导致的cGMP含量减少。而环孢素A及西地那非可分别抑制ET-1刺激的PASMCs增殖。结论 ET-1可通过激活Calcineurin/NFAT信号通路介导ET-1诱发的PDE5表达,进而降低cGMP含量,引起PASMCs增殖;而抑制Calcineurin或PDE5可提高cGMP水平,抑制ET-1诱导的PASMCs增殖。

Objective To examine whether calcineurin/NFAT signaling pathway mediates endothelin-1 （ET-1）-induced proliferation of pulmonary artery smooth muscle ceils （PASMCs） by regulating phosphodiesterase-5 （PDE5） and the effect of the selective calcineurin inhibitor cyclosporine A and PDE5 inhibitor sildenafil on ET-l-induced PASMC proliferation. Methods PASMCs were treated with ET-1 to stimulate their proliferation with or without prior treatment of the cells with CsA or sildenafil. Calcineurin activity in the cells was measured using a calcineurin activity assay kit, PDE5 expression examined using immunoblotting, and cGMP level detected using a cGMP direct immunoassay kit. PASMC proliferation following the treatments was determined using [3H]thymidine incorporation assay. Results ET-1 caused a 2.05-fold increase in the cellular calcineurin activity, a 1.80-fold increase in PDE5 expression, and a 3.20-fold increase in the DNA synthesis rate, and reduced the cGMP level by 67%. Pretreatment of the cells with Cycloporine blocked the effects of ET-1, and PDE5 inhibition by sildenafil pretreatment also abolished ET-l-induced reduction of cGMP level in the cells. Both Cycloporine and sildenafil suppressed ET-l-stimulated PASMC proliferation. Conclusion Activation of calcineurin/NFAT signaling pathway mediates ET-l-induced PASMC proliferation by stimulating PDE5 expression, which further degrades cGMP. Both Cycloporine and sildenafil can suppress ET-l-sfimulated PASMC proliferation in vitro.