人支气管平滑肌细胞内mRNA结合蛋白人抗原R对α-平滑肌肌动蛋白表达的影响

mRNA-binding protein Human-antigen R regulates α-SMA expression in human bronchia smooth muscle cells

目的 观察人支气管平滑肌细胞（HBSMC）内mRNA结合蛋白人抗原R（HuR）对α-平滑肌肌动蛋白（α-SMA）表达的影响.方法 体外培养HBSMC,根据血小板源性生长因子（PDGF）对其刺激时间分别记为0、6、12、24 h组.采用实时荧光定量PCR法检测各组HuR与α-SMA mRNA的表达、Western印迹法检测各组HuR与α-SMA蛋白的表达.干扰RNA法观察抑制HuR蛋白表达后PDGF刺激下对细胞α-SMA蛋白表达的影响.结果 PDGF时间依懒性增强HuR的表达,0、6、12、24 h组全细胞HuR蛋白及mRNA相对表达量分别为0.23 ±0.09、0.42 ±0.11、0.93 ±0.21、1.37±0.28及1.00±0.00、1.09±0.03、1.16 ±0.03、1.27±0.02（均P＜0.05）;各组α-SMA蛋白及mRNA相对表达量也呈时间依赖性增强（1.03±0.08、1.20±0.09、1.39±0.11、1.58±0.10及1.00±0.00、1.17 ±0.02、1.23±0.02、1.45±0.03,均P＜0.05）.HuR特异地干扰RNA转染细胞后,HuR表达下调,PDGF诱导的α-SMA表达相应减弱.结论 PDGF可增加HBSMC中HuR及α-SMA的表达,HuR参与PDGF诱导的α-SMA表达过程.

Objective To investigate the role of mRNA binding protein Human-antigen R （HuR） in the over-expression of α-Smooth muscle actin （ot-SMA） stimulated by Platelet-derived Growth Factor （PDGF） in cultured human bronchia smooth muscle cells.Methods Human bronchia smooth muscle cells cultured in vitro were divided into 0,6,12 and 24 h groups according to the time of PDGF treatment.Total HuR protein and total α-SMA protein expression were detected by Western blot.Total HuR mRNA and total α-SMA mRNA level were determined by quantitative real time-polymerase chain reaction.RNA interference technology was used to down-regulate HuR protein level to study the protective effect of HuR in PDGFstimulated α-SMA protein expression.Results PDGF up-regulated the expression of HuR in a timedependent manner.The relative expression levels of whole-cell HuR protein and mRNA in 0,6,12,24 h groups were0.23 ±0.09,0.42 ±0.11,0.93 ±0.21,1.37 ±0.28;1.00 ±0.00,1.09 ±0.03,1.16± 0.03,1.27 ± 0.02 （all P 〈 0.05）.The relative expression levels of α-SMA protein and mRNA in 0,6,12,24 h group also showed an increase trend marked in a time-dependent manner （1.03 ± 0.08,1.20 ± 0.09,1.39 ±0.11,1.58 ±0.10;1.00±0.00,1.17 ±0.02,1.23 ±0.02,1.45 ±0.03;all P〈0.05）.Using RNA interference technology to down-regulate HuR protein level,there was a decrease in α-SMA protein expression.Conclusion PDGF stimulation can increase the expression of HuR and α-SMA in the smooth muscle cells,and HuR protein is involved in the expression of c-SMA protein stimulated by PDGF.