STAT3信号分子在创伤弧菌侵入树突状细胞中的作用

Effects of STAT3 on Vibrio vulnificus invasion in dendritic cells

目的研究创伤弧菌(Vibrio vulnificus,Vv)侵入小鼠树突状细胞株(dendritic cell,DC)时,树突状细胞凋亡率变化与STAT3的表达,探讨STAT3信号分子在创伤弧菌侵入树突状细胞中的作用。方法建立创伤弧菌(Vv1.1758株)与小鼠树突状细胞(DC 2.4株)混合培养模型,采用FITC-Annexin V/PI、RT-PCR法和免疫荧光法分别检测不同混合培养时间段,树突状细胞凋亡率、STAT3 mRNA的表达和p-STAT3蛋白表达量的变化。结果创伤弧菌Vv 1.1758株与DC2.4混合培养2 h后,细菌即可侵入DC2.4,细菌侵入率明显升高(P<0.05);混合培养2 h,4 h,6 h后,细胞凋亡率分别为(38.3±8.7)%,(58.4±10.8)%和(69.1±13.5)%;混合培养2 h后,STAT3 mRNA相对表达量开始下降,p-STAT3蛋白表达水平呈显著下降趋势,STAT3出现胞核内转移现象。结论创伤弧菌可降低树突状细胞内STAT3 mRNA的表达量,抑制胞内p-STAT3蛋白的表达,从而诱导树突状细胞凋亡,可能是创伤弧菌的重要致病机制之一。

Objective In this study,the co-culture model of mouse dendritic cell and V.vulnificus 1.1758 strain was established.Methods After the establishment of this model,FITC-Annexin V / PI,RT-PCR and immune fluorescent technique were adopted to detect the apoptosis rate,STAT3 mRNA expression,p-STAT3 protein expression and nuclear translocation of STAT3 in DC2.4 cells respectively,during different co-culture times.Results The invading rate increased rapidly at 2h co-culture（P 0.05）.Apoptosis rates of DC2.4 cells are（38.3 ±8.7）%,（58.4 ±10.8）% and（69.1 ± 13.5） % at 2h,4h and 6h,respectively,after mixed cultivation with V.vulnificus 1.1758.At 2h co culture,expression of STAT3 mRNA started to decrease.In the meanwhile,the expression of p STAT3 protein declined significantly,which was detected by immune fluorescent technique.Also,the nuclear translocation of STAT3 in DC2.4 cells could be observed.Conclusion Vibrio vulnificus could decrease STAT3 mRNA expressions and inhibit p-STAT3 protein expressions in DC cells,inducing the dendritic cell undergoes apoptosis.This may be an important mechanism of pathogenicity of Vibrio vulnicufis.