脓肿分枝杆菌经Toll样受体2介导的JNK/ERK信号通路诱导巨噬细胞表达肿瘤坏死因子α和白细胞介素8

Stimulated expressions of tumor necrosis factor α and interleukin 8in macrophages challenged by Mycobacterium abscessus through TLR2,JNK and ERK pathways

为探讨脓肿分枝杆菌脓肿亚种和马赛亚种经Toll样受体2(Toll-like receptor 2,TLR2)介导的c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)和细胞外信号调节激酶(extracellular signal-regulated kinase,ERK)诱导THP-1巨噬细胞内肿瘤坏死因子α(tumor necrosis factorα,TNF-α)和白细胞介素8(interleukin8,IL-8)表达的相关分子机制,本研究将脓肿分枝杆菌脓肿亚种和马赛亚种感染THP-1巨噬细胞,细菌与巨噬细胞最佳感染之比为感染复数(multiplicity of infection,MOI)=3,用荧光定量聚合酶链反应(polymerase chain reaction,PCR)检测THP-1巨噬细胞感染两细菌亚种6h后的胞内TNF-α和IL-8mRNA水平,以及分别阻断TLR2、JNK和ERK信号蛋白后TNF-α和IL-8mRNA水平的变化。结果显示,脓肿分枝杆菌脓肿亚种和马赛亚种作用于THP-1巨噬细胞6h后,均可诱导细胞内TNF-α和IL-8mRNA水平显著上调,差异有统计学意义(P<0.05);分别阻断TLR2、JNK和ERK信号蛋白,脓肿亚种感染THP-1巨噬细胞后胞内TNF-α和IL-8mRNA上调水平出现明显抑制,差异有统计学意义(P<0.05);分别阻断TLR2和JNK信号蛋白,马赛亚种感染THP-1巨噬细胞后胞内TNF-α和IL-8mRNA上调水平均出现明显抑制,差异有统计学意义(P<0.05);而阻断ERK信号蛋白后,马赛亚种组仅见IL-8mRNA水平明显抑制,差异有统计学意义(P<0.05),而TNF-αmRNA水平未见明显变化,差异无统计学意义(P>0.05)。本研究提示,脓肿分枝杆菌脓肿亚种和马赛亚种均可作用于TLR2,诱导THP-1细胞内TNF-α和IL-8mRNA水平上调,脓肿亚种可经JNK和ERK信号蛋白诱导TNF-αmRNA上调,马赛亚种可经JNK信号蛋白诱导TNF-αmRNA上调;脓肿亚种和马赛亚种诱导IL-8mRNA上调可能与JNK和ERK信号蛋白相关。

The purpose of the current study is to investigate the molecular mechanisms of tumor necrosis factor α （TNF-α） and interleukin 8 （IL-8） mRNA expressions in THP-1 macrophages challenged by Mycobacterium abscessus subsp.abscessus （Mabs） and Mycobacterium abscessus subsp.massiliense （Mmass）.The role of Toll-like receptor 2 （TLR2）-mediated c-Jun N-terminal kinase （JNK） and extracellular signal-regulated kinase （ERK） signaling pathways were investigated.First, THP-1 macrophages were cultured in the presence of Mabs and Mmass to stimulate cytokine expression.The mRNA expression levels of TNF-α and IL-8 were analyzed using quantitative reverse transcriptase-polymerase chain reaction （qRT-PCR） after 6 h.The levels of TNF-α and IL-8 mRNA after administration of anti-TLR2 mAb, JNK signaling inhibitor SP600125 and ERK signaling inhibitor U0126 were also detected.The results demonstrated that the levels of TNF-α and IL-8 mRNA in THP-1 cells were significantly upregulated by Mabs and Mmass for 6 h （P〈0.05）.The stimulated expressions of both TNF-α and IL-8 were significantly downregulated by anti-TLR2 mAb, JNK inhibitor or ERK inhibitor, respectively.It was thus concluded that both Mabs and Mmass could upregulate TNF-α and IL-8 mRNA expressions through TLR2-mediated JNK and ERK pathways.