血管紧张素II介导的大鼠血管平滑肌细胞STAT1激活与核转位

Activation and nuclei translocation of STAT1 induced by Ang II in rat VSMCs

目的检测血管紧张素II(Ang II)介导的大鼠血管平滑肌细胞(VSMC)增殖过程中信号转导和转录活化因子-1(STAT1)的激活与核转位。方法本文采用Western印迹、非同位素凝胶电泳(EMSA)和免疫荧光染色的方法,观察Ang II刺激大鼠主动脉VSMC前后,细胞中STAT1的活化状态与定位。结果VSMC经Ang II干预后,胞内磷酸化的STAT1(p-STAT1)蛋白表达增加(P<0.01),达峰后随时间梯度逐渐下降,Ang II干预15 min后检测到胞核内有蛋白-DNA复合物形成。这一反应可被血管紧张素II 1型受体(AT1)阻滞剂Losartan以及Jak2抑制剂AG490抑制(P<0.01)。免疫荧光染色结果也显示Ang II干预后p-STAT1主要在胞核内表达。结论Ang II可以通过和AT1受体结合,激活Jak/STAT通路,在Ang II介导的大鼠VSMC增殖过程中发挥作用。

AIM In vascular smooth muscle cells （VSMCs）, the Janus kinase （Jak）/signal transducer and activators of transcription（STAT） is one of the induction of early growth response genes, and STAT proteins play an essential role in angiotensin Ⅱ-induced VSMC proliferation . To identify the activation and the nuclei translocation of signal transducers and activators of transcriptionl （ STAT1 ） induced by Ang Ⅱ in the rat aortic smooth muscle cells. METHODS The cultured rat aortic smooth muscle cells were stimulated with Ang Ⅱ. The protein expression of phosphorylation STAT1 was detected by Western blotting, STAT-SIE binding activation was detected by electrophoretic mobility shift assay and the nuclei translocation of phosphorylated STAT1 was identified by immunofluorescence. RESULTS Western blotting showed that the expression of phosphorylation-STAT1 in vascular smooth muscle cells （VSMCs） had an increase in Ang Ⅱ-stimulated VSMCs（P 〈 0.01 ）and the increase was blocked by Losartan（ P 〈 0.01 ） and AG490（P 〈 0.01 ）. EMSA and immunofluorescence show that after a 15-minute stimulation with Ang Ⅱ, DNA-protein compounds were generated in the nucleus. This response could be blocked by Losartan. CONCLUSION Jak-STAT signal transduction pathways participate and play a crucial role in the mechanism of Ang Ⅱ-induced VSMCs proliferation.