Akt1/p27^(kip1) Pathway Mediates Inhibition of LXA_4 on TNF-α-induced Proliferation of Rat Mesangial Cells

Akt1/p27^(kip1)途径介导脂氧素A_4抑制TNF-α所致的系膜细胞增殖(英文)

Objective:To examine whether lipoxin A 4(LXA 4) 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 LXA 4 actions. Methods: Glomerular mesangial cells of rat were cultured and treated with TNF-α(10 ng/ml), with or without preincubation with LXA 4 at different concentrations. Cell proliferation was evaluated by monotetrazolium (MTT) colorimetric assay. The expression of cyclin E mRNA was measured by RT-PCR. Phosphorylated Akt1(Thr308) and p27 kip1 were analyzed by Western blotting. Results: TNF-α-stimulated proliferation of mesangial cells was inhibited by LXA 4 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 LXA 4. Threonine phosphorylated Akt1 proteins at 308 site stimulated by TNF-α was reduced by LXA 4. TNF-α-induced decrements in expression of p27 kip1 proteins was ameliorated by LXA 4 in a dose-dependent manner. Conclusion: TNF-α-induced proliferation of rat mesangial cells can be inhibited by TXA 4 through the mechanism of Akt 1/p27 kip1 pathway-dependent signal transduction.

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 ml)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Westernblot检测 30 8位苏氨酸(Thr30 8)磷酸化的蛋白激酶Akt1及细胞周期负调控蛋白P2 7kipl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 30 8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P2 7kipl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 P2 7kipl信号转导途径。