The role of sodA and sodB in Aeromonas hydrophila resisting oxidative damage to survive in fish macrophages and escape for further infection
The role of sodA and sodB in Aeromonas hydrophila resisting oxidative damage to survive in fish macrophages and escape for further infection
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DOI：
10.1016/j.fsi.2019.03.021
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发表时间：
2019-05
影响因子：
4.7
通讯作者：
Meimei Zhang;Yingxue Qin;Lixing Huang;Q. Yan;Leilei Mao;Xiaojin Xu;Suyun Wang;Mengmeng Zhang;Liwei Chen
中科院分区：
文献类型：
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作者：
Meimei Zhang;Yingxue Qin;Lixing Huang;Q. Yan;Leilei Mao;Xiaojin Xu;Suyun Wang;Mengmeng Zhang;Liwei Chen
有几种细菌被定义为细胞外病原体;然而，近年来已经证实，它们具有存活能力并逃避宿主吞噬细胞的攻击，从而引起进一步感染。先前的研究表明，嗜水气单胞菌可以在鱼类巨噬细胞中存活，但其机制尚不清楚。本研究对A. shRNA可稳定沉默p53 α B11。细胞内sodA-RNAi和sodB-RNAi的存活率分别下降91.8%和74.9%，免疫逃逸率分别下降32%和92%。同时，与吞噬野生型菌株的巨噬细胞相比，吞噬sodA-RNAi和sodB-RNAi的鱼巨噬细胞中的活性氧（ROS）分别增加了40%和32.6%。与sodA相比，sodB在A.无氧化应激;然而，当暴露于氧化应激时，sodA表达的上调幅度显著高于sodB。随着甲基紫精浓度的增加，sodA-RNAi和sodB-RNAi的存活率显著降低。sodA和sodB的表达不影响A的生长。而抑制sodA和sodB的表达则导致氧化应激下细菌生长略有下降。这些结果表明：（1）sodA和sodB在细菌抵抗宿主吞噬细胞ROS损伤的过程中发挥重要作用，使其得以存活甚至逃离鱼类巨噬细胞;（2）sodB在A.在无氧化应激的条件下，sodA的表达在氧化应激条件下上调更为显著，sodA和sodB在细菌抵抗ROS的过程中贡献相当;（3）sodA和sodB在细菌的胞内存活过程中相互补充、协同作用，保护细菌免受ROS的损伤。
Several bacteria have been defined as extracellular pathogens; however, in recent years, it has been confirmed that they have the ability to survive and escape the attack of host phagocytes, thus causing further infection. Previous studies have shown that Aeromonas hydrophila could survive in fish macrophages; however, the mechanism remains unknown. In this study,sodAandsodBof the strainA. hydrophilaB11 were stable silenced by shRNA. The survival rates of intracellularsodA-RNAi andsodB-RNAi decreased by 91.8% and 74.9% and the immune escape rates decreased by about 32% and 92% respectively. At the same time, reactive oxygen species (ROS) in fish macrophages that phagocytosedsodA-RNAi andsodB-RNAi increased by 40% and 32.6%, respectively, compared to those of macrophages that phagocytosed the wild-type strain. Compared tosodA,the expression ofsodBpredominates inA. hydrophilawithout oxidative stress; however, when exposed to oxidative stress, the magnitude of up-regulation ofsodAexpression is significantly higher than that ofsodB. With increased of methyl viologen concentration, the survival rates ofsodA-RNAi andsodB-RNAi were significantly decreased. The expressions ofsodAand sodBdid not affect the growth ofA. hydrophilawithout oxidative stress, but the inhibition ofsodAandsodBexpression led to a slight decrease in bacterial growth under oxidative stress. These results indicated that (1)sodAandsodBplay an important role in the process of bacterial resistance to ROS damage in host phagocytic cells, allowing them to survive or even escape fish macrophages; (2) thesodBexpression was dominant inA. hydrophilawithout oxidative stress, thesodAexpression was up-regulated more significantly under oxidative stress, andsodAand sodBcontributed equally to the process of bacterial resistance to ROS; (3)sodAandsodBcomplement each other and cooperate in the process of intracellular survival of bacteria to protect against ROS damage.