伤寒杆菌IVB型菌毛激活PKC信号通路诱导THP-1细胞IL-6表达

目的 探讨伤寒杆菌IVB型菌毛激活PKC信号通路诱导THP-1细胞IL-6表达。方法将THP-1细胞分别与有IVB型菌毛的A21-6菌、缺失IVB型菌毛的pilS^-菌共同孵育，分别检测蛋白激酶C(PKC)活性、IL-6产量及IL-6 mRNA的表达水平；用PKC抑制剂DECA预处理THP-1细胞，然后再以A21-6菌诱导，测定PKC活性和IL-6产量。结果THP-1细胞经有IVB型菌毛的A21-6菌刺激后，IL-6的产生水平、mRNA的表达水平以及PKC活性均显著高于相应的处理组。PKC活性在一定范围内呈时效关系，刺激10min后即明显升高，并于30min左右达到峰值。PKC抑制剂DECA一定程度上能够抑制IVB型菌毛诱导的THP-1细胞PKC活性和IL-6产生水平。结论IVB型菌毛在伤寒杆菌诱导单核／巨噬细胞产生IL-6过程中是一种重要的刺激因素；PKC参与了该过程的细胞内信号转导。

Type IVB pili of Salmonella Typhi induce interleukin-6 expression in THP-1 cells by activating PKC signal pathway

Objective To investigate the IL-6 expression in THP-1 cells induced by Type IVB pili of Salmonella Typhi through activation of PKC. Methods THP-1 cells were incubated with the Salmonella Typhi strain A21-6 or pilS -. The activation of PKC, production of IL-6, and expression level of IL-6 mRNA in the supernate were detected. The A21-6 strain was also used to stimulate the THP-1 cells or cells pretreated with PKC inhibitor DECA for different time interval, and then the PKC activation and IL-6 production in the supernate were assayed. Results The A21-6 strain had significant effect on the IL-6 production and PKC activity. PKC acitivity in differentiated THP-1 cells was increased at 10 min poststimulattion and reach to the peak value at 30 min. The PKC inhibitor DECA reduced both the IL-6 production and PKC activity obviously. Conclusion The type IVB pili of Salmonella Typhi play an important role in secretion of proinflammatory cytokine IL-6, and PKC-dependent pathway participates in that process.