Listeriolysin O Pore-Forming Activity Is Required for ERK1/2 Phosphorylation DuringListeria monocytogenesInfection
Listeriolysin O Pore-Forming Activity Is Required for ERK1/2 Phosphorylation DuringListeria monocytogenesInfection
复制标题
单核细胞增生李斯特菌感染期间，ERK1/2 磷酸化需要李斯特菌溶血素 O 成孔活性
DOI：
10.3389/fimmu.2020.01146
复制
发表时间：
2020-06-03
影响因子：
7.3
通讯作者：
Song, Houhui
中科院分区：
文献类型：
--
作者：
Cheng, Changyong;Sun, Jing;Song, Houhui
李斯特菌溶血素O（LLO）是一种胆固醇依赖性细胞溶解素，可介导李斯特菌逃逸。单核细胞生成素从吞噬体中分离出来，使细菌能够在宿主体内生长。LLO是一种多功能的工具，允许李斯特菌触发多种细胞反应。在本研究中，李斯特菌感染引起的Caco-2细胞上ERK 1/2的快速磷酸化被证明高度依赖于LLO活性。单独添加纯化的重组LLO可强烈诱导这种效应，外源性胆固醇可抑制这种效应。缺乏PEST序列，已知严格控制LLO的细胞毒性，不影响ERK 1/2激活。然而，在胆固醇结合基序中具有突变的重组非细胞溶解性LLOT 515 AL 516 A不能触发这种应答。缺乏大部分细胞溶解活性的重组LLON 478 AV 479 A也不能激活ERK 1/2磷酸化，并且当蛋白质浓度达到细胞溶解水平时，这种作用可以被挽救。用LLO缺陷突变体（Delta hly）或补充LLO的突变体（T515 AL 516 A）感染废除了细菌激活ERK 1/2的能力。然而，用保留部分孔形成能力并可在细胞内生长的补充LLON 478 AV 479 A的Delta hlymutant感染能够触发ERK 1/2磷酸化。总之，这些数据表明，ERK 1/2激活由L.单核细胞生成依赖于LLO的透化活性，更重要的是与LLO的胆固醇结合基序相关。
Listeriolysin O (LLO) is a cholesterol-dependent cytolysin that mediates escape ofL. monocytogenesfrom phagosomes and enables the bacteria to grow within the host. LLO is a versatile tool allowingListeriato trigger several cellular responses. In this study, rapid phosphorylation of ERK1/2 on Caco-2 cells caused byListeriainfection was demonstrated to be highly dependent on LLO activity. The effect could be strongly induced by adding purified recombinant LLO alone and could be inhibited by exogenous cholesterol. Lack of the PEST sequence, known to tightly control cytotoxicity of LLO, did not affect ERK1/2 activation. However, the recombinant non-cytolytic LLOT515AL516A, with mutations in the cholesterol-binding motif, was unable to trigger this response. Recombinant LLON478AV479A, which lacks most of the cytolytic activity, also failed to activate ERK1/2 phosphorylation, and this effect could be rescued when the protein concentration reached a cytolytic level. Infection with an LLO-deficient mutant (Delta hly) or the mutant complementing LLO(T515AL516A)abrogated the capacity of the bacteria to activate ERK1/2. However, infection with the Delta hlymutant complementing LLON478AV479A, which retained partial pore-forming ability and could grow intracellularly, was capable of triggering ERK1/2 phosphorylation. Collectively, these data suggest that ERK1/2 activation byL. monocytogenesdepends on the permeabilization activity of LLO and more importantly correlates with the cholesterol-binding motif of LLO.