金黄色葡萄球菌α-toxin(Hla)促进皮肤组织中IL-19表达上调的作用机制研究

Staphylococcus aureus α-toxin (Hla) promote IL-19 expression in a murine skin infection model

目的探究金黄色葡萄球菌α-toxin(Hla)促进皮肤组织中IL-19表达上调的作用机制。方法采用WT S.Aureus、△Hla S.aureus(Hla缺失菌株)以及PBS感染Balb/c小鼠背部皮肤,收集感染后第1、3、7天的皮肤组织,HE染色检测组织炎性病理损伤,q RT-PCR和ELISA分别检测IL-19、IL-1β的m RNA和蛋白水平的表达。分离小鼠骨髓的中性粒细胞,分别用WT S.Aureus、△Hla S.aureus以及meida(不含菌液的培养基)刺激6 h后,q RT-PCR、ELISA和Western blot检测IL-1β的表达。不同浓度IL-1β刺激角质形成细胞PAM 2-12后,q RT-PCR和ELISA分别检测IL-19的表达。结果△Hla S.aureus组与WT S.aureus组相比,其皮肤损伤的面积减小,炎性细胞浸润和脓肿形成减少。同时q RT-PCR和ELISA检测发现,△Hla S.aureus组与WT S.aureus组相比,IL-19的m RNA和蛋白表达水平显著降低(P<0.01)。体外中性粒细胞刺激发现,△Hla S.aureus组与WTS.aureus组相比,IL-1β蛋白表达水平显著降低(P<0.01)。体外IL-1β刺激角质形成细胞PAM 2-12发现,与不刺激组相比,IL-19的m RNA和蛋白表达水平显著增加(P<0.01),并呈剂量依赖性。结论金黄色葡萄球菌分泌的α-toxin能够作用于中性粒细胞,促进了IL-1β的表达,IL-1β的过表达作用于皮肤的角质形成细胞,从而促进了IL-19的上调,可能参与了银屑病的发生与发展。

This study aimed to explore the mechanism of Staphylococcus aureus or-toxin promoting the expression of IL-19 in skin tissues. The Balb/c mice were infected with WT S. aureus, A Hla S. dtureus or PBS at days 1, 3, 7 postinfection, then the skin lesion was collected and HE staining was employed to evaluate the histological lesion, and the mRNA and protein levels of IL-19 and IL-1β were detected by qRT-PCR and ELISA. Neutrophils were isolated from mouse bone marrow and stimulated with WT S. aureus, △A Hla S. aureus or meida, and the expression of IL-1β was detected by qRT-PCR, ELISA and Western blotting; mouse keratinocytes PAM 2-12 were stimulated with different doses IL-1β, and the mRNA and protein level of IL-19 were detected by qRT-PCR and ELISA. Our results showed that the inflammatory cells infiltration and abscess formation were less and the IL-19 and IL- 1 βmRNA and protein levels were lower in A Hla S. aureus group than those in the A Hla S. aureus group （P〈0.01）; the expression of IL-1β in neutrophils stimulated with A Hla S. aureus was significantly down-regulated than those stimulated with WT S. aureus （P〈0.01）; IL-19 expression in keratinocytes PAM 2-12 stimulated with IL-1β was significantly up-regulated in a dose-dependent manner in vitro. Taken together, staphylococcus aureus α-toxin promotes IL-1 β expression in neutrophils, and IL-1β enhances IL-19 expression inkeratinocytes. Thus staphylococcus aureus eL-toxin involves in the development and progression of psoriasis.