Edwardsiella piscicida enters non-phagocytic cells via a macropinocytosis-involved hybrid mechanism
Edwardsiella piscicida enters non-phagocytic cells via a macropinocytosis-involved hybrid mechanism
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杀鱼爱德华氏菌通过巨胞饮作用混合机制进入非吞噬细胞
DOI：
10.1128/jb.00548-18
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发表时间：
2019
影响因子：
3.2
通讯作者：
Qin Liu
中科院分区：
文献类型：
--
作者：
Tianjian Hu;Lingzhi Zhang;Wei Wang;Dahai Yang;Jingfan Xiao;Yuanxing Zhang;Xiaohong Liu;Qin Liu
杀鱼爱德华氏菌是一种重要的病原菌，可感染从鱼类到人类的多种宿主。最近的研究表明，E.杀鱼素能侵入并存活于多种非吞噬细胞内，但其内在化机制仍知之甚少。在这里，我们使用HeLa细胞作为非吞噬细胞模型来研究致病性大肠杆菌使用的内吞策略。杀鱼线虫分离物EIB 202。使用光学显微镜和电子显微镜相结合，我们观察到EIB 202感染后HeLa细胞中明显的膜皱褶和F-肌动蛋白重排。我们还发现EIB 202的内化显著依赖于Na+/H+交换体的活性和与巨胞饮相关的多个胞内信号事件，表明E.杀鱼素利用宿主巨胞饮途径进入HeLa细胞。此外，使用抑制性药物和shRNAs阻断特定的内吞途径，我们发现在E.杀鱼素进入，其进入需要发动蛋白和膜胆固醇。总之，这些数据表明，E。杀鱼素通过巨胞饮作用和小窝蛋白依赖的涉及胆固醇和发动蛋白的内吞作用进入非吞噬细胞，提高了对E.杀鱼素与非吞噬细胞相互作用。重要提示细菌内化是突破宿主细胞防御的第一步。因此，研究细菌内化的机制有助于加深对细菌致病机制的认识。本文研究了杀鱼爱德华氏菌对非吞噬细胞的内化过程。结果表明，E.杀鱼素可以通过巨胞饮作用和小窝蛋白介导的内吞作用内化到非吞噬细胞中，胆固醇和发动蛋白参与了这一过程。这些结果揭示了一种新的抑制大肠杆菌的方法。为进一步研究细菌的致病性奠定了基础。
Edwardsiella piscicida is an important pathogen that infects a wide range of hosts from fish to human. Recent studies demonstrated that E. piscicida can invade and survive within multiple nonphagocytic cells, but the internalization mechanism remains poorly understood. Here, we used HeLa cells as a nonphagocytic cell model to investigate the endocytic strategy used by the pathogenic E. piscicida isolate EIB202. Using a combination of optical and electron microscopy, we observed obvious membrane ruffles and F-actin rearrangements in HeLa cells after EIB202 infection. We also revealed that EIB202 internalization significantly depended on the activity of Na+/H+exchangers and multiple intracellular signaling events related to macropinocytosis, suggesting that E. piscicida utilizes the host macropinocytosis pathway to enter HeLa cells. Further, using inhibitory drugs and shRNAs to block specific endocytic pathways, we found that a caveolin-dependent but not clathrin-dependent pathway is involved in E. piscicida entry and that its entry requires dynamin and membrane cholesterol. Together, these data suggest that E. piscicida enters nonphagocytic cells via macropinocytosis and caveolin-dependent endocytosis involving cholesterol and dynamin, improving the understanding of how E. piscicida interacts with nonphagocytic cells.IMPORTANCEBacterial internalization is the first step in breaking through the host cell defense. Therefore, studying the mechanism of bacterial internalization improves the understanding of the pathogenic mechanism of bacteria. In this study, the internalization process on nonphagocytic cells byEdwardsiella piscicidawas evaluated. Our results showed that E. piscicida can be internalized into nonphagocytic cells via macropinocytosis and caveolin-mediated endocytosis, and that cholesterol and dynamin are involved in this process. These results reveal a new method for inhibiting E. piscicida infection, providing a foundation for further studies of bacterial pathogenicity.