Akt1/p27kip1途径介导脂氧素A4抑制TNF-α所致的系膜细胞增殖

目的：研究脂氧素A4(LXA4)是否抑制肿瘤坏死因子-α(TNF-α)所致的肾小球系膜细胞增殖，并探讨LXA4作用的信号转导机制。方法：用不同浓度的脂氧素A4预外理培养的大鼠肾小球系膜细胞，再加入TNF-α(10ng／m1)共同孵育；或单用TNF-α刺激肾小球系膜细胞。用四甲基偶氮唑蓝(MTT)法检测细胞增殖；用RT-PCR法检测细胞周期素E与mRNA表达；用Westemblot检测308位苏氨酸(Thr308)磷酸化的蛋白激酶Aktl及细胞周期负调控蛋白P27^kipl表达量。结果：LXA4呈剂量依赖性地抑制TNF-α诱导的系膜细胞增殖。在系膜细胞增殖同时TNF-α引起的细胞周期素E的蛋白表达也被LXA4下调。LXA4减少TNF-α诱导的肾小球系膜细胞中308位苏氨酸磷酸化的Akt1蛋白。LXA4呈剂量依赖性地阻止TNF-α所致的P27^kipl表达下调。结论：LXA4能够抑制TNF-α所致的大鼠系膜细胞的增殖，其机制依赖于Akt1／P27^kipl信号转导途径。

Akt1/p27kip1 Pathway Mediates Inhibition of LXA4 on TNF-α-induced Proliferation of Rat Mesangial Cells

Objective: To examine whether lipoxin A4 (LXA4) has an inhibitory effect on tumor necrosis factor-α(TNF-α)-induced proliferation of glomerular mesangial cells of rat, and explore the molecular mechanisms of signal pathway in LXA4 actions. Methods: Glomerular mesangial cells of rat were cultured and treated with TNF- α(10 ng/ml),with or without preincubation with LXA4 at different concentrations. Cell proliferation was evaluated by monotetrazolium (MTr) colorimetric assay. The expression of cyclin E mRNA was measured by RT-PCR. Phosphorylated Akt1 (Thr308) and p27kip1 were analyzed by Western blotting. Results: TNF- α- stimulated proliferation of mesangial cells was inhibited by LXA4 in a dose-dependent manner. The marked increments in cyclin E mRNA expression induced by TNF-α during proliferation of mesangial cells were down-regulated by LXA4. Threonine phosphorylated Akt1 proteins at 308 site stimulated by TNF-α was reduced by LXA4. TNF-α-induced decrements in expression of p27kip1 proteins was ameliorated by LXA4 in a dose-dependent manner. Conclusion: TNF-α-induced proliferation of rat mesangial cells can be inhibited by TXA4 through the mechanism of Akt1/p27kip1 pathway-dependent signal transduction.