Bacterial cell wall component-induced tolerance represents an important protective mechanism during microbial infection.Tolerance induced by the TLR2 agonist bacterial lipoprotein(BLP)has been shown to attenuate the i...Bacterial cell wall component-induced tolerance represents an important protective mechanism during microbial infection.Tolerance induced by the TLR2 agonist bacterial lipoprotein(BLP)has been shown to attenuate the inflammatory response,and simultaneously to augment antimicrobial function,thereby conferring its protection against microbial sepsis.However,the underlying mechanism by which BLP tolerance augments bactericidal activity has not been fully elucidated.Here,we reported that the induction of BLP tolerance in murine macrophages upregulated the expression of Rab20,a membrane trafficking regulator,at both the mRNA and protein levels upon bacterial infection.The knockdown of Rab20 with Rab20 specific siRNA(siRab20)did not affect the phagocytosis of Escherichia coli(E.coli),but substantially impaired the intracellular killing of the ingested E.coli in BLP-tolerized macrophages.Furthermore,Rab20 was associated with GFP-E.coli containing phagosomes,and BLP tolerization resulted in the enhanced maturation of GFP-E.coli-containing phagosomes associated with Rab20 and strong lysosomal acidification.The knockdown of Rab20 substantially diminished lysosome acidification and disturbed the fusion of GFP-E.coli containing phagosomes with lysosomes in BLP-tolerized macrophages.These results demonstrate that Rab20 plays a critical role in BLP tolerization-induced augmentation of bactericidal activity via promoting phagosome maturation and the fusion of bacteria containing phagosomes with lysosomes.展开更多
目的:探讨Toll受体1/2(Toll like receptor1/2,TLR1/2)信号对荷瘤小鼠来源的CD8^+T细胞功能的影响及其可能机制。方法:利用小鼠Lewis肺癌细胞株3LL建立小鼠肺癌荷瘤模型,MACS分选小鼠脾CD8^+T细胞;体外经PBS或TLR1/2激动剂BLP刺激后,Rea...目的:探讨Toll受体1/2(Toll like receptor1/2,TLR1/2)信号对荷瘤小鼠来源的CD8^+T细胞功能的影响及其可能机制。方法:利用小鼠Lewis肺癌细胞株3LL建立小鼠肺癌荷瘤模型,MACS分选小鼠脾CD8^+T细胞;体外经PBS或TLR1/2激动剂BLP刺激后,Real-time PCR和流式细胞术分别从基因和蛋白水平检测CD8^+T细胞的TLR分子表达;用ELISA和流式细胞术检测经PBS或BLP刺激后的CD8^+T细胞分泌细胞因子和增殖的能力,并用关键信号分子抑制剂分析可能的分子机制。结果:与PBS对照组相比,TLR1/2激动剂BLP不但有效上调荷瘤机体CD8^+T细胞TLR1和TLR2分子的基因水平[TLR1:(0.353±0.015)vs(0.101±0.017),P<0.01;TLR2:(0.232±0.031)vs(0.080±0.004),P<0.05]及蛋白水平(P<0.05),而且显著促进CD8^+T细胞分泌功能性细胞因子[IFN-γ:(2 375±305)vs(850±50),P<0.05;IL-2:(1 600±200)vs(350±50),P<0.05]和增殖的能力(P<0.05),这一效应依赖于NF-KB和P38通路。结论:TLR1/2信号直接作用于荷瘤小鼠的CD8^+T细胞并促进其功能,该研究既丰富了TLR的作用范围,也为基于TLR激动剂的肿瘤生物治疗提供了实验依据。展开更多
细菌脂蛋白是一种脂质修饰的膜蛋白,参与细胞膜合成等多种重要生理过程。脂蛋白形成过程依赖于Lol转运系统,该蛋白最先在细胞质中以前体的形式合成,然后在细胞膜上被加工为成熟脂蛋白,锚定于细菌外膜周质侧。Lol系统由LolA-E五种蛋白组...细菌脂蛋白是一种脂质修饰的膜蛋白,参与细胞膜合成等多种重要生理过程。脂蛋白形成过程依赖于Lol转运系统,该蛋白最先在细胞质中以前体的形式合成,然后在细胞膜上被加工为成熟脂蛋白,锚定于细菌外膜周质侧。Lol系统由LolA-E五种蛋白组成,其中脂蛋白在周质空间中依赖伴侣蛋白LolA进行转运,LolA将脂蛋白以"mouth to mouth"的方式从LolCDE转运至LolB,进而完成脂蛋白定位。重点对周质分子伴侣LolA结构、参与的转运体系及其生物学功能进行综述,旨在通过对脂蛋白转运分子机制的理解为感染性疾病的治疗提供更多的药物靶点。展开更多
基金This work was supported by the National Natural Science Foundation of China(81471901,81272149)the Guangdong Provincial Natural Science Foundation(2015A030311031,2018A0303130289)+1 种基金the Guangdong Provincial Key Laboratory Construction Project of China(2014B030301044)the South Wisdom Valley Innovative Research Team Program(CXTD-001).
文摘Bacterial cell wall component-induced tolerance represents an important protective mechanism during microbial infection.Tolerance induced by the TLR2 agonist bacterial lipoprotein(BLP)has been shown to attenuate the inflammatory response,and simultaneously to augment antimicrobial function,thereby conferring its protection against microbial sepsis.However,the underlying mechanism by which BLP tolerance augments bactericidal activity has not been fully elucidated.Here,we reported that the induction of BLP tolerance in murine macrophages upregulated the expression of Rab20,a membrane trafficking regulator,at both the mRNA and protein levels upon bacterial infection.The knockdown of Rab20 with Rab20 specific siRNA(siRab20)did not affect the phagocytosis of Escherichia coli(E.coli),but substantially impaired the intracellular killing of the ingested E.coli in BLP-tolerized macrophages.Furthermore,Rab20 was associated with GFP-E.coli containing phagosomes,and BLP tolerization resulted in the enhanced maturation of GFP-E.coli-containing phagosomes associated with Rab20 and strong lysosomal acidification.The knockdown of Rab20 substantially diminished lysosome acidification and disturbed the fusion of GFP-E.coli containing phagosomes with lysosomes in BLP-tolerized macrophages.These results demonstrate that Rab20 plays a critical role in BLP tolerization-induced augmentation of bactericidal activity via promoting phagosome maturation and the fusion of bacteria containing phagosomes with lysosomes.
文摘细菌脂蛋白是一种脂质修饰的膜蛋白,参与细胞膜合成等多种重要生理过程。脂蛋白形成过程依赖于Lol转运系统,该蛋白最先在细胞质中以前体的形式合成,然后在细胞膜上被加工为成熟脂蛋白,锚定于细菌外膜周质侧。Lol系统由LolA-E五种蛋白组成,其中脂蛋白在周质空间中依赖伴侣蛋白LolA进行转运,LolA将脂蛋白以"mouth to mouth"的方式从LolCDE转运至LolB,进而完成脂蛋白定位。重点对周质分子伴侣LolA结构、参与的转运体系及其生物学功能进行综述,旨在通过对脂蛋白转运分子机制的理解为感染性疾病的治疗提供更多的药物靶点。
