阻断哮喘患儿外周血淋巴细胞IL-4/IL-4R通路对转录因子STAT4 STAT6表达的影响研究

Effects of blocking IL-4/IL-4R pathway on the expression of transcription factors STAT4 and STAT6 in PBL in asthmatic patients

目的探讨支气管哮喘白介素4/白介素4受体(IL-4/IL-4R)通路过度活化与转录因子STAT4和STAT6表达的关系。方法2007年2—10月,对重庆医科大学附属儿童医院收治的25例哮喘患儿通过RT-PCR、IF和ELISA方法,检测经过抗人IL-4R单克隆抗体(mhIL-4RAb)干预前后外周血淋巴细胞中STAT4和STAT6 mRNA的表达、pSTAT4和pSTAT6表达量的变化及培养上清液中IL-4和γ干扰素(IFN-γ)质量浓度。并对同期体检的30名对照组儿童进行同样检测。结果(1)对哮喘组、干预组和对照组患儿淋巴细胞培养上清液中IL-4及IFN-γ水平分别进行比较,哮喘组与后两组差异有统计学意义(均P<0.05);后两组之间差异无统计学意义(P>0.05)。(2)对3组淋巴细胞中STAT4 mRNA、STAT6 mRNA表达进行比较:哮喘组STAT4 mRNA表达量显著低于后两组,STAT6 mRNA表达则显著高于后两组(均P<0.05),后两组间比较差异无统计学意义(P>0.05)。(3)免疫荧光显示哮喘组淋巴细胞中pSTAT4表达显著低于后两组(均P<0.05);pSTAT6表达水平则显著提高,后两组间比较差异无统计学意义(P>0.05)。结论阻断哮喘患儿IL-4/IL-4R通路能够通过影响pSTAT4和pSTAT6的表达影响IL-4和IFN-γ的分泌,从而扭转Th2细胞分化亢进的状态。pSTAT4和pSTAT6的表达之间存在相互拮抗。IL-4及IFN-γ分泌量的变化可以反向影响STAT6及STAT4的转录。

Objective To explore the relationship between the overactive IL-4/IL-4R pathway in asthmatic patients and the expression of transcription factors STAT4 and STAT6. Methods The expressions of STAT4 and STAT6 mRNA in lymphocytes were assayed by RT-PCR. pSTAT4 and pSTAT6 expression levels were assayed by IF in 25 asthmatic patients interfered by mhIL-4RAb or not and 30 healthy children, IL-4 and IFN-γ concentrations in the supernatant were detected by ELISA. Results Concentration of IL-4 and IFN-γ in lymphocyte supernatant of asthmatic group was significantly distinct compared to that of interfered group and control group （P 〈 0.05） , but no significant difference was demonstrated between interfered group and control group （P 〉 0.05）. RT-PCR results revealed that STAT4 mRNA expression in asthmatic group was significantly decreased compared to intervention group and control group （P 〈 0.05） and the levels of STAT6 mRNA expression in asthmatic group was significantly increased compared to the other two groups （P 〈 0.05）, no difference between intervention group and control group （P 〉 0.05）. According to the results of IF technique, the expression of pSTAT4 was significantly declined and pSTAT6 were significantly increased in asthmat- ic group compared to interfered group and control group （P 〈 0.05）, no difference between interfered group and control group （P 〉 0.05）. Conclusion mhIL-4RAb can influence the expression of pSTAT4 and pSTAT6 through blocking IL-4/IL-4R pathway and influence the excretion of IL-4 and IFN-γ, and then change the tendency of Th2 polarization in asthma. There is reversely-working effect between pSTAT4 and pSTAT6 expressions. Concentration of IL-4 and IFN-γ can reversely influence transcription of STAT6 and STAT4.