新蛋白质合成介导知母活性成分对M_2受体稳定性的调节作用

目的 探讨知母活性成分ZMS提高CHOm2细胞毒蕈碱样乙酰胆碱2型受体 (M_2受体) mRNA表达的机制.方法 体外培养至80% ～90%融合的CHOm2细胞分为ZMS 1组(单纯添加1×10~(-5) mol/L ZMS作用24 h)、ZMS 2组(添加1×10~(-5) mol/L ZMS作用24 h后加入1 μg/mL环己酰亚胺作用12 h)、ZMS 3组(加入1 μg/mL 环己酰亚胺预处理4 h后加入1×10~(-5) mol/L ZMS作用24 h),以上各组分别设立对照组(以等体积DMSO替代ZMS,其他处理与相应ZMS组相同).各组细胞培养基中均加入放线菌素D抑制mRNA合成,于不同时间点收集CHOm2细胞,Real-time PCR检测M_2受体mRNA相对表达量并计算半衰期.结果 与相应对照组比较,ZMS 1组和ZMS 2组CHOm2细胞M_2受体mRNA的半衰期明显延长,分别为(4.75±0.54)h vs(2.13±0.23)h和(5.43±1.13)h vs (2.46±0.09) h(均P<0.05);添加1 μg/mL 环己酰亚胺预处理的ZMS 3组CHOm2细胞M2受体mRNA半衰期的(3.06±0.23)h与其相应对照组的(3.00±0.20)h比较,差异无统计学意义(P>0.05).结论 ZMS提高M2受体mRNA的稳定性需要有新蛋白质合成的参与.

ZMS regulation of M_2 muscarinic receptor stability mediated by de novo synthesis of protein

Objective To explore the mechanism of ZMS regulation of M_2 muscarinic receptor mRNA expression. Methods In vitro cultured CHOm2 cells were divided into ZMS 1 group (treatment with 1 × 10~(-5) mol/L ZMS for 24 h), ZMS 2 group (treatment with 1 × 10~(-5) mol/L ZMS for 24 h and 1 μg/mL cycloheximide for 12 h) and ZMS 3 group (treatment with 1 μg/mL cycloheximide for 4 h and 1 × 10 ~(-5) mol/L ZMS for 24 h), and their corresponding control groups were also established (substitution of ZMS by DMSO). Actinomycin D was added to cultured CHOm2 cells of each group to inhibit the synthesis of mRNA. CHOm2 cell samples were taken at different time points, the relative expression of M_2 receptor mRNA was detected by Real-time PCR, and half life of M_2 receptor mRNA was calculated. Results Compared with corresponding control groups, the half life of M_2 receptor mRNA of CHOm2 cells in ZMS 1 group and ZMS 2 group was significantly prolonged (4.75h± 0.54) h vs (2.13 ±0.23) h, P<0.05; (5.43 ±1.13) h vs (2.46 ±0.09) h, P<0.05]. There was no significant difference in half life of M_2 receptor mRNA of CHOm2 cells between ZMS 3 group and its corresponding control ( 3.06 ±0.23) h vs (3.00 ± 0.20) h, P > 0.05]. Conclusion De novo protein synthesis is required for the enhancement of M_2 receptor mRNA stability regulated by ZMS.