CATH-2抑制金黄色葡萄球菌诱导IL-1β分泌的机制研究

Mechanism study on inhibition of Staphylococcus aureus-induced IL-1βsecretion by cathelicidins-2

为探讨鸡源cathelicidin-2(CATH-2)抑制金黄色葡萄球菌(Staphylococcus aureus,S.aureus)诱导IL-1β成熟与分泌的机制,采用S.aureus体外感染野生型(WT)小鼠腹腔巨噬细胞的模型,CATH-2预处理巨噬细胞2 h后感染S.aureus,通过ELISA、Real-time PCR和Western blot研究CATH-2对S.aureus诱导IL-1β分泌的影响。ELISA结果显示,CATH-2显著降低了S.aureus诱导的IL-1β、IL-6、IL-1α和IL-12表达水平(P<0.05)。RT-PCR结果显示,CATH-2显著降低了巨噬细胞中S.aureus诱导的IL-1βmRNA表达水平(P<0.05);Western blot结果显示,CATH-2显著降低了巨噬细胞中S.aureus诱导的pro-IL-1β、IL-1β和pro-caspase-1表达水平(P<0.05)。进一步的研究结果显示,CATH-2显著降低了巨噬细胞中S.aureus诱导的NF-κB(p65)和MAPK(JNK1/2)的总蛋白和磷酸化蛋白的表达(P<0.05)。这些结果表明CATH-2通过抑制NF-κB和MAPK信号通路活性抑制炎症小体激活,进而抑制IL-1β分泌。

To explore the mechanism of chicken cathelicidins-2(CATH-2)inhibiting Staphylococcus aureus(S.aureus)-induced IL-1βmaturation and secretion,primary peritoneal macrophages of mice infected with S.aureus were pretreated with CATH-2 for 2 h and then infected with S.aureus to investigate the effect of CATH-2 on S.aureus-induced IL-1βsecretion through assays of ELISA,RT-PCR and Western blot.The results of ELISA showed that CATH-2 significantly reduced S.aureus-induced inflammatory cytokines including IL-1β,IL-6,IL-1αand IL-12(P<0.05).The results of RT-PCR showed that CATH-2 significantly downregulated S.aureus-induced IL-1βmRNA expression(P<0.05).The results of Western blot showed that CATH-2 remarkably decreased S.aureus-induced protein expression of pro-IL-1β,IL-1βand pro-caspase-1.Further findings showed that CATH-2 significantly reduced S.aureus-induced expression of total and phosphorylated proteins of NF-κB(p65)and MAPK(JNK1/2)in macrophages(P<0.05).These results demonstrate that CATH-2 inhibits inflammasome activation through the inhibition of NF-κB and MAPK signaling pathways,which results in the inhibition of IL-1βsecretion.