肺炎链球菌触发肺Ⅱ型上皮细胞F-actin细胞骨架重排

TYPE Ⅱ PNEUMOCYTES FILAMENTOUS ACTIN REARRANGEMENTS INDUCED BY STREPTOCOCCUS PNEUMONIAE

目的 :通过体外实验 ,研究肺炎链球菌 (Streptococcus pneumoniae,S.pn)是否可触发肺 型上皮细胞 (A5 4 9)信号转导途径触发微丝肌动蛋白 (filam entous actin,F- actin)细胞骨架重排 ,进而侵袭 A5 4 9细胞 ,并初步分析触发 A5 4 9细胞 F- actin细胞骨架重排的细菌亚组分。方法 :采用 F- actin特异性 FITC-phalloidin荧光染料 ,观察 S.pn作用 A5 4 9细胞前后的 F- actin细胞骨架重排情况 ,依照重排百分率得分标准以 (% )表示 ;用 F- actin细胞骨架重排抑制剂细胞松弛素 D预处理 A5 4 9细胞 ,观察 S.pn对 A5 4 9细胞侵袭的改变情况 ;用变溶菌素提取 S.pn细胞壁以观察其对 F- actin细胞骨架重排的影响。结果 :S.pn作用A5 4 9细胞后 ,经 FITC- phalloidin荧光染色 ,F- actin细胞骨架呈黄绿色块状聚集 ,对照细胞呈现均匀黄绿色荧光外观 ;F- actin细胞骨架重排抑制剂细胞松弛素 D可明显降低 S.pn对 A5 4 9细胞的侵袭 ,在其浓度为 0 .2 5 μg/ m l时 ,未得到可测的细菌数 ;S.pn细胞壁作用 A5 4 9细胞后 ,经 FITC- phalloidn荧光染色 ,F-actin细胞骨架呈黄绿色块状聚集 ,二者存在剂量依赖性。结论 :S.pn及其细胞壁亚组分可触发 A5 4 9细胞F- actin细胞骨架重排 ,进而侵袭 A5 4

Objective:Streptococcus pneumoniae(S pn) invasion of host cells plays an important role in its pathogenesis,but the mechanism of invasion is poorly understood.The research investigated whether S pn can provoke filamentous actin(F actin) rearrangements in vitro .In this study,we still identified cell wall subcomponents of S pn ,which can lead to above the events Methods:Labelled F actin with FITC phalloidin,we observed F actin rearrangements by S pn adhesion of type Ⅱ pneumocytes(A549) S pn invasion of A549 cells was determined by pretreating A549 cells with cytochalasin D Result:Intact S pn can promote F actin rearrangements Cytochalasin D is able to prevent S pn invasion of A549 cells Conclusion: S pn and its cell wall subcomponents can provoke F actin rearrangements,which will further lead to S pn invasion of A549 cells