先兆子痫患者血清血管紧张素Ⅱ 1型受体自身抗体对血管平滑肌细胞ERK1/2信号途径的激动效应

Autoantibodies against AT_1 Receptor from Patients with Preeclampsia Induce Activation of Extracellular Signal-regulated Kinases(ERK1/2) in Cultured Rat Vascular Smooth Muscle Cells

目的探讨血管紧张素Ⅱ1型受体(AT1受体)的自身激动性抗体(AT1-AAs)激动培养的大鼠血管平滑肌细胞(VSMCs)AT1受体并激活细胞外信号调节激酶1/2(ERK1/2)信号途径的能力。方法采用亲和层析法提取先兆子痫患者血清中的AT1-AAs。培养大鼠主动脉VSMCs。应用血管紧张素Ⅱ(AngⅡ)或AT1-AAs刺激培养的细胞。而后,采用免疫印迹法测定细胞中ERK1/2的表达;逆转录PCR检测细胞c-fos基因的表达;应用钙离子的荧光探针Fluo-3/AM负载培养VSMCs,应用共聚焦显微镜检测细胞荧光强度变化以反映细胞内游离钙水平的变化。结果 AT1-AAs能够发挥与血管紧张素Ⅱ类似的效应,能够激动AT1受体,促使ERK1/2的磷酸化并促进其下游的c-fos在VSMCs中的表达;并且ERK1/2的磷酸化一定程度依赖于钙离子信号。结论由于ERK1/2信号通过促进血管炎症、纤维化及血管收缩造成血管重塑,AT1-AAs可能通过该途径参与先兆子痫患者的循环障碍。

Objective Preeclampsia（PE）is a disorder of pregnancy characterized by hypertension,proteinuria and placental abnormalities.Recent studies have shown that antibodies directed against angiotensin Ⅱ type 1（AT1）receptors are also highly associated with PE.AT1 receptor agonistic antibodies（AT1-AAs）can bind and activate AT1 receptors.We tested the ability that AT1-AAs,could stimulate the AT1 receptor and activate the pathway of extracellular signal-regulated kinase 1/2（ERK1/2）in cultured rat vascular smooth muscle cells（VSMCs）.Methods AT1-AAs from patients with PE were obtained by affinity purification.AT1-AAs or Ang Ⅱ was used to stimulate the cultured rat VSMCs.After stimulation,activation of ERK1/2 was evaluated by immunoblotting.The expression of c-fos was assessed by reverse transcriptase polymerase chain reaction.Fluo-3/AM,a Ca2＋ fluorescent indicator was used to load VSMCs for monitoring changes of intracellular Ca2＋ mobilization under the confocal microscopy.Results AT1-AAs exerted similar effects like Ang Ⅱ on the ERK1/2 phosphorylation and downstream c-fos expression in rat VSMCs;and ERK1/2 phosphorylation was Ca2＋-dependent to some extent.Conclusion As ERK1/2 contribute to arterial remodeling through enhancing VSMCs proliferation,inflammation,fibrosis and constriction,AT1-AAs are suggested to involve in disorders of systemic circulation in PE.