肺泡上皮细胞减轻巨噬细胞抗结核分枝杆菌感染中TLR信号介导的炎症反应  

Alveolar epithelial cells alleviate TLR signal mediated inflammatory in process of mononuclear macrophage infected by H37Rv

作　　者：孙颖飞[1] 杨易[1] 程龙[1] 贾元元[1] 任奇杰 李勇[1] 刘晓明[1] 王玉炯[1] 

机构地区：[1]宁夏大学生命科学学院西部生物资源保护与利用教育部重点实验室,宁夏银川750021

出　　处：《中国兽医学报》2016年第6期964-970,共7页Chinese Journal of Veterinary Science

基　　金：国家自然科学基金资助项目(31160515)

摘　　要：本研究模拟体内肺泡的气液相环境,采用肺脏上皮细胞与巨噬细胞的气液相共培养模型,探讨肺脏上皮细胞对巨噬细胞抗结核分枝杆菌感染的免疫调节作用。建立人肺泡上皮细胞A549与人单核细胞U937分化而来的巨噬细胞的气液相共培养模型,利用人结核分枝杆菌H37Rv株分别感染A549细胞、U937细胞和共感染A549/U937细胞,然后利用定量反转录PCR(qRT-PCR)、ELISA和Western blot检测巨噬细胞U937中的Toll样受体(TLR)信号分子及其下游炎症因子的表达变化。结果显示,H37Rv分别感染共培养模型中的A549细胞和U937细胞都能明显上调U937巨噬细胞中TLR信号分子TLR2、TLR4、TLR6、TLR8、MyD88和TRAF6,及其下游炎症因子NFκB、TNFα、IL-1α、IL-2、IL-6、IL-10和IL-12α的表达;但当H37Rv共感染上皮细胞和巨噬细胞,H37Rv诱导的U937巨噬细胞的上述因子表达较单独其感染的巨噬细胞显著下降。结果表明,在上皮细胞和巨噬细胞共培养体系中,结核分枝杆菌H37Rv分别感染人A549上皮细胞和U937巨噬细胞都能激发巨噬细胞的TLR信号及其下游的炎症反应,但2种细胞共感染H37Rv,上皮细胞感染后能够降低巨噬细胞的TLR信号活性,并减轻后者的炎症反应。由此可见,肺泡内上皮细胞与巨噬细胞之间可能存在某种相互调控机制,避免抗感染过程中的过度炎症反应以保持肺泡内细胞的组织及其功能的稳态。In order to explore the immunoregulatory role of alveolar epithelial cells in macrophages in response to mycobacterial infections in an air-liquid interface（ALI）model mimicking the in vivo environment,an ALI of alveolar epithelial cells and macrophages co-culture model was employed.An ALI co-culture model of A549 human alveolar epithelial cells and U937 mononuclear cell-derived macrophages was first generated,A549 and U937cells of the co-culture model were separately infected or co-infected with Mycobacterium tuberculosis reference strain H37 Rv.The immune responses of U937 macrophages were ascertained by determining the expression of Tolllike receptor（TLR）signaling molecules and inflammatory cytokines using qRT-PCR,ELISA and Western blot assays.The results showed that the expression of all tested TLR signaling molecules TLR2,TLR4,TLR6,TLR8,MyD88 and TRAF6,as well as their down-stream inflammatory cytokines NFκB,TNFα,IL-1α,IL-2,IL-6,IL-10 and IL-12αin U937 cells were elevated when the A549 alveolar epithelial cells or U937 macrophages were infected with H37 Rv.Intriguingly,when both of A549 cells and U937 cells were infected with H37 Rv,the inflammatory responses of U937macrophages were alleviated in comparison with they were infected alone in the ALI co-culture model,as determined by the expression of above signaling molecules and cytokines.In this alveolar epithelial/macrophage co-culture model,the TLR signaling mediated inflammatory responses in U937 macrophage were activated when either of A549 cells or U937 cells were separately infected with H37 Rv,but the H37Rv-induced inflammatory responses in U937 macrophages could be alleviated when they were co-infected with A549 cells with mycobacteria.This finding suggests that there may be an interaction between alveolar epithelial cells and macrophages to regulate immune response of target cells in response to mycobacterial infections,which may prevent an excessive inflammatory reaction of host cells and maintain the tissue and functional homeostasis of

关 键 词：肺泡上皮细胞 肺泡巨噬细胞 结核分枝杆菌 Toll样受体信号 炎症反应 

分 类 号：S852.61[农业科学—基础兽医学] R535[农业科学—兽医学]