ERK1/2信号通路在甲状旁腺激素致人近曲小管上皮细胞分泌纤溶酶原激活物抑制剂1中的作用

目的 从体外观察ERK信号通路在甲状旁腺激素（PTH）致人近曲小管上皮细胞（HK-2）合成纤溶酶原激活物抑制物1（PAI-1）中的作用。 方法 以HK-2细胞株为研究对象，用不同浓度PTH（10-8、10-9、10-10、10-11、10-12 mol/L）作用细胞48 h，以及10-10 mol/L PTH作用细胞不同时间（12、24、36、48、72 h），分别用RT-PCR法检测PAI-1 mRNA表达，Western印迹法检测PAI-1蛋白表达。以10-10 mol/L PTH作用细胞48 h，分别观察细胞ERK1/2抑制剂预处理前后磷酸化（p）ERK1/2、PAI-1mRNA及蛋白的变化情况。 结果 10-12 mol/L PTH可促进细胞在基因及蛋白水平合成PAI-1，随着PTH浓度逐渐上升，PAI-1mRNA及蛋白浓度均相应增加，以10-10 mol/L PTH组刺激作用最显著，分别为对照组的4.01倍和3.81倍（均P < 0.01）。但随着PTH浓度进一步增加，PAI-1mRNA及蛋白浓度却随之下降。10-10 mol/L PTH作用细胞，12 h时有少量PAI-1表达，72 h时达峰值，并呈时间依赖性，分别为0 h组的4.06倍和4.03倍（均P < 0.01）。10-10 mol/L PTH作用细胞48 h，有大量的p-ERK1/2合成（P < 0.01），经ERK1/2抑制剂预处理后，PAI-1及ERK均显著下降（均P < 0.01），但仍高于对照组（均P < 0.05）。 结论 ERK信号通路部分参与PTH致HK-2细胞合成PAI-1的作用。

Role of ERK1/2 kinase system in the expression of the type-1 plasminogen activator inhibitor induced by parathormone in human renal tubular epithelial cells

Objective To explore the role of ERK1/2 in the expression of the type-1 plasminogen activator inhibitor (PAI-1) induced by parathormone(PTH) in human renal tubular epithelial cell line HK-2 cells. Methods Various concentrentions of PTH and manifold durations were applied in the test. The expression of PAI-1 mRNA and protein in HK-2 cells was measured by RT-PCR and Western blotting, respectively. Besides, ERK1/2 protein was detected by Western blotting before the ERK1/2 inhibitor incubated with the HK-2 cells or after. Results The expression of PAI-1mRNA and protein was gradually up-regulatad along with the increasing concentrations of PTH (10-12-10-10 mol/L). The maximum level of PAI-1 mRNA and protein was detected in 10-10 mol/L PTH and was 4.01 and 3.81 times of control group. Otherwise, the decreased expression of PAI-1 was found while the concentrations of PTH were beyond 10-10 mol/L. The levels of PAI-1 mRNA and protein were increased in pace with time from 12 to 72 hour, in time-dependent manner, which was 4.06 (12 h) and 4.03 (72 h) times of 0 hour group. The levels of ERK1/2 and PAI-1 were ascended after 10-10 mol/L PTH incubated with the HK-2 cells (all P<0.01). Howerver, both of them decended after cells were pretreated by the ERK1/2 inhibitor (all P<0.01), but were still higher than those of control group (all P<0.05). Conclusion ERK1/2 kinase system partly participates in the regulation of PAI-1 induced by PTH in HK-2 cells.