1,25-二羟基维生素D_3对人肾小球系膜细胞增殖、周期的影响及其机制

Effects of 1,25(OH)_2D_3 on proliferation and cell cycle of human glomerular mesangial cells

目的观察1,25-二羟维生素D_3(1,25-(OH)_2D_3)对人肾小球系膜细胞株增殖及细胞周期的影响,并探讨其可能作用机制。方法对数生长期人肾小球系膜株细胞分为A、B、C、D组,分别加入终浓度为10^(-8)mol/L的1,25(OH)_2D_3+含5%FBS的L-DMEM培养基、5 mg/L雷帕霉素+含5%FBS的L-DMEM培养基、5 mg/L雷帕霉素+终浓度为10^(-8)mol/L 1,25(OH)_2D_3+含5%FBS的L-DMEM培养基。给药48 h时观测各组细胞增殖及细胞周期分布,检测各组细胞真核细胞翻译起始抑制因子4E结合蛋白(4E-BP1)、磷酸化4E-BP1蛋白。结果给药48h时A、B、C组的细胞凋亡率分别为38.02%、55.62%、99.23%,组间比较,P均<0.05。给药48 h时,A、B、C组G_1期细胞所占比例明显高于D组(P均<0.05),S、G_2/M期细胞所占比例明显低于D组(P均<0.05);B、C组G_1期细胞所占比例明显高于A组(P均<0.05),S、G_2/M期细胞所占比例明显低于D组(P均<0.05);C组G_1期细胞所占比例明显高于B组(P均<0.05),S、G_2/M期细胞所占比例明显低于B组(P均<0.05)。A、B、C组细胞4EBP1、磷酸化4E-BP1蛋白相对表达量及磷酸化4E-BP1/4E-BP1均低于D组(P均<0.05);B、C组细胞4E-BP1、磷酸化4E-BP1蛋白相对表达量及磷酸化4E-BP1/4E-BP1均低于A组(P均<0.05);C组细胞4E-BP1、磷酸化4EBP1蛋白相对表达量及磷酸化4E-BP1/4E-BP1均低于B组(P均<0.05)。结论 1,25(OH)_2D_3可抑制人肾小球系膜细胞株的增殖,阻滞细胞周期于G_1期,其机制可能为1,25-(OH)_2D_3下调4E-BP1的表达。

Objective To investigate the effects of 1,25-dihydroxyvitamin D_3[1,25（ OH）_2D_3] on cell proliferation and cell cycle of human glomerular mesangial cells and the possible mechanism. Methods Human mesangial cells in the logarithmic phase were cultured in vitro and then were divided into four groups： groups A,B,C and D. Four groups were separately added with such culture mediums： group A with 10^（-8）mol/L 1,25（ OH）_2D_3＋ L-DMEM medium containing 5%fetal bovine serum（ FBS）,group B with 5 μg/m L rapamycin ＋ L-DMEM medium containing 5% FBS,group C with 5μg/m L rapamycin ＋ 10^（-8）mol/L 1,25（ OH）_2D_3＋ L-DMEM medium containing 5% FBS,and group D with the L-DMEM medium containing 5% FBS. After 48-hour administration,we observed the cell proliferation and cell cycle distribution in each group. The protein expression of eukaryotic cell translation initiation inhibitory factor 4E binding protein（ 4E-BP1）and phosphorylated 4E-BP1（ P-4EBP1） in cells was determined by Western blotting. Results At 48 h,the cell apoptosis rates of the groups A,B and C were 38. 02%,55. 62% and 99. 23%,respectively,and significant difference was found between them（ P〈0. 05）. At 48 h,the proportion of cells in the G_1 phase of groups A,B and C was significantly higher than that of group D（ all P〈0. 05）,the proportion of cells in the S,G_2/M phase was clearly lower than that of group D（ all P〈0. 05）. The proportion of cells in the G_1 phase of groups B and C was significantly higher than that of group A（ all P〈0. 05）,and the proportion of cells in the S,G_2/M phase was clearly lower than that of group D（ all P〈0. 05）. The proportion of cells in the G_1 phase of group C was higher than that of group B（ all P〈0. 05）,and the proportion of cells in the S,G_2/M phase was lower than that of group B（ all P〈0. 05）. The 4E-BP1 and P-4E-BP1 protein expression and P-4E-BP1/4E-BP1 of groups A,B and C was lower than that of group D（ all P〈0. 05）. The 4E-BP1 and P-4E-BP1 protein expression and P-4E-BP1/4E-BP1 of groups B and C was lower than that of group A（ all P〈0. 05）. The 4E-BP1 and P-4E-BP1 protein expression and P-4E-BP1/4E-BP1 of group C was lower than that of group B（ all P〈0. 05）. Conclusion1,25（ OH）_2D_3may inhibit the glomerular mesangial cell proliferation and block the cell cycle in G_1 phase through downregulating the expression of 4E-BP1.