甲状旁腺激素通过丝裂原活化蛋白激酶信号通路诱导人近曲小管上皮细胞结缔组织生长因子表达

目的 观察甲状旁腺激素（PTH）对人肾小管上皮细胞分泌结缔组织生长因子（CTGF）的影响，并探讨丝裂原活化蛋白激酶（MAPK）信号途径在此过程中的作用。 方法 采用实时定量PCR、Western印迹、报告基因等技术，观察PTH诱导人近端肾小管上皮细胞系HK-2细胞CTGF表达的情况。使用信号通路抑制剂PD98059、U0126阻断信号通路以明确PTH发挥作用的信号途径。 结果 正常HK-2细胞有基础水平的CTGF mRNA和蛋白表达，PTH刺激后其表达水平显著增加。10-10 mol/L PTH作用12 h后，荧光素酶活性较对照组明显升高[（1.8884±0.0780）比（0.9891±0.0300） A，P ＜ 0.01]。正常HK-2细胞有少量p-ERK1/2表达，PTH刺激后p-ERK1/2表达明显升高，以10-10 mol/L PTH作用30 min时效应最强；MAPK通路抑制剂PD98059、U0126作用后，CTGF mRNA、蛋白、基因启动子表达均明显下降。 结论 PTH可诱导HK-2细胞CTGF表达，其作用可能是通过MAPK信号通路来实现的。

Expression of connective tissue growth factor induced by parathyroid hormone via MAPK signaling pathway in human renal proximal tubular cells

Objective To evaluate the effect of parathyroid hormone (PTH) on the expression of connective tissue growth factor (CTGF) in human renal tubular epithelial cells, and to explore the role of MAPK signaling pathway. Methods Real time RT-PCR, Western blot, and reporter gene assay were employed to detect PTH-induced CTGF expression in HK-2 cells. Inhibitors (PD98059 and U0126) of MAPK signaling pathway were used to confirm involved signal pathway. Results HK-2 cells had basic expression level of CTGF mRNA and protein, which were increased significantly after treatment with PTH. The luciferase activity was up-regulated to a higher level as compared with control group after treatment with 10-10 mol/L PTH for 12 h [(1.8884±0.0780) vs (0.9891±0.0300) A, P<0.01]. Moreover, a small amount of p-ERK1/2 was detected in normal HK-2 cells, but it was increased significantly in response to PTH activation, most remarkably when treated with 10-10 mol/L PTH for 30 min. Inhibitors of MAPK signaling pathway, PD98059 and U0126, noticeably inhibited the expression of CTGF mRNA and protein as well as gene promoters in HK-2 cells. Conclusion PTH can induce higher expression of CTGF in HK-2 cells probably via MAPK signaling pathway.