MEK/ERK1/2在LPS抑制NRK-52E肾小管上皮细胞增殖中的作用

【摘要】 目的 探讨脂多糖(LPS)对大鼠NRK-52E肾小管上皮细胞增殖的影响及MEK/ERK1/2信号途径的调节作用。方法 不同剂量LPS按不同时间刺激NRK-52E细胞,并以MEK特异性抑制剂U0126干预。使用cell counting kit-8(cck-8)试剂检测细胞增殖,Western blot检测NRK-52E细胞ERK1/2、Akt蛋白磷酸化水平。结果 LPS在0.001、0.01 mg·L-1作用72 h对NRK-52E细胞增殖无明显影响,在0.1、1.0 mg·L-1抑制NRK-52E细胞增殖;MEK特异性抑制剂U0126显著抑制NRK-52E细胞增殖,其作用在2.5、5、10、20 ?滋M浓度之间无显著差异。U0126预处理加强LPS对NRK-52E细胞增殖的抑制作用。LPS诱导NRK-52E细胞ERK1/2和Akt磷酸化;U0126单独或联合LPS处理NRK-52E细胞72 h阻断ERK1/2蛋白磷酸化,伴有pAkt蛋白水平上调。结论 MEK/ERK1/2可能在LPS抑制NRK-52E细胞增殖的过程中起保护作用。

The role of MEK/ERK1/2 in LPS-induced suppression of renal tubular epithelial NRK-52E cell proliferation

Objective To investigate the role of LPS on proliferation of renal tubular epithelial cells NRK-52E and the implication of MEK/ERK1/2 in the process. Methods NRK-52E cells were cultured and challenged with LPS at different concentrations and for the indicated time courses. A specific MEK inhibitor, U0126, was used either alone or as a pretreatment followed by adding LPS to the medium to test the involvement of MEK/ERK1/2 in the proliferation of NRK-52E ceils exposed to LPS. Cell proliferation was evaluated using cell counting kit-8 （CCK-8） reagents. The protein levels of ERK1/2, Akt, phosphorylated ERK1/2 and Akt （pERK1/2, pAkt）, were detected by Western blot using specific antibodies. Results LPS inhibited NRK-52E cell proliferation at the concentrations from 0.1 to 1.0 rag.L-1 after treatment for 72 hours. NRK-52E cell proliferation was also inhibited by U0126 at the concentrations from 2.5 to 20μM after treatment for 72 hours,without significant difference between the tested concentrations. LPS-induced suppression of NRK-52E cell proliferation was further aggravated by pretreatment with U0126. LPS induced phosphorylation of both ERK1/2 and Akt, peaked at 30 min. LPS-induced phosphorylation of ERK1/2 was blunted by U0126 at 72 h, while phosphorylation of Akt was elevated in cells treated with U0126 alone as well as in combination with LPS. Conclusion LPS suppressed NRK-52E cell proliferation, in which MEK/ERK1/2 might play a protective role.