甲基汞通过miRNA对人胚胎神经干细胞细胞周期相关基因表达的调控

Methylmercury Tunes Cell Cycle Regulated Gene Expressions in Human Embryonic Neural Stem Cells through miRNAs

[目的]通过研究甲基汞对人胚胎神经干细胞mi RNA表达的影响,探讨低剂量甲基汞对神经干细胞细胞周期调控基因的调节作用。[方法]以0、10、50 nmol/L甲基汞染毒人胚胎神经干细胞24 h后,用MTT法测定甲基汞对细胞活力影响,应用逆转录多聚酶链反应(RT-PCR)检测甲基汞对细胞周期调控基因(p16、p21)的m RNA的表达水平影响,利用实时荧光定量多聚酶链反应技术检测调控p16、p21的mi RNA(mi R-24、mi R-106a)的表达情况。[结果]50 nmol/L甲基汞染毒组细胞活力降低为对照组的53.5%,差异有统计学意义(P<0.05);p16与p21基因的m RNA表达水平随着甲基汞染毒浓度的升高而升高,差异均有统计学意义(P<0.05),但10 nmol/L与50 nmol/L组的p16基因表达差异无统计学意义。mi R-24、mi R-106a的表达水平随着甲基汞染毒浓度的升高而降低,差异有统计学意义(P<0.05)。[结论]50 nmol/L的甲基汞可以引起人胚胎神经干细胞增殖抑制,并可能通过mi RNA调节细胞周期调控基因的表达。

[Objective] To investigate the impact on alteration of cell cycle regulated genes induced by low-level methylmercury via the expression of micro RNAs of human embryonic neural stem cells. [Methods] After treatment with 0, 10, and 50 nmol/L methylmercury for 24 h to human embryonic neural stem cells, cell viability was measured with methyl thiazolyl tetrazolium（MTT） assay. m RNA expressions of cell cycle regulated genes p16 and p21 were determined in human embryonic stem cells after the methylmercury exposure by reverse transcription polymerase chain reaction（RT-PCR）. Expressions of mi RNA（mi R-24 and mi R-106a） were determined using quantitative real time polymerase chain reaction（q RT-PCR） assay. [Results] Compared with the control group, the cell viability was significantly reduced by 53.5% in the 50 nmol/L methylmercury treatment group（P〈0.05）. Compared with the control group, RT-PCR analysis revealed significant methylmercury-induced up-regulations of p16 and p21 m RNA expressions（P〈0.05）, but no difference in p16 expression level was found between the 10 nmol/L and the 50 nmol/L treatment. The expressions of mi R-24 and mi R-106 a were significantly lower with the increases in methylmercury concentrations（P〈0.05）. [Conclusion] Methylmercury treatment at 50 nmol/L could restrain the self-renewal ability of neural stem cells and tune cell cycle regulators transcription through altering the expression of mi RNAs.