Wang Suyun, Yan Qingpi, Zhang Meimei, Huang Lixing, Mao Leilei, Zhang Mengmeng, Xu Xiaojin, Chen Liwei, Qin Yingxue
Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, China.
J Fish Dis. 2019 Jun;42(6):895-904. doi: 10.1111/jfd.12991. Epub 2019 Mar 28.
Survival in host macrophages is an effective strategy for pathogenic bacteria to spread. Aeromonas hydrophila has been found to survive in fish macrophages, but the mechanisms remain unknown. In this paper, the roles and possible mechanisms of IcmF in bacterial survival in fish macrophages were investigated. First, a stable silencing strain icmF-RNAi was constructed by shRNA and RT-qPCR confirmed the expression of icmF was down-regulated by 94.42%. The expression of Hcp, DotU and VgrG was also decreased in icmF-RNAi. The intracellular survival rate of the wild-type strain was 92.3%, while the survival rate of icmF-RNAi was only 20.58%. The escape rate of the wild-type strain was 20%, while that of the icmF-RNAi was only 7.5%. Further studies indicated that the expression of icmF can significantly affect the adhesion, biofilm formation, motility and acid resistance of A. hydrophila, but has no significant effect on the growth of A. hydrophila even under the stress of H O . The results indicated that IcmF of A. hydrophila not only acts as a structural protein which participates in virulence-related characteristics such as bacterial motility, adhesion and biofilm formation, but also acts as a key functional protein which participates in the interaction between bacteria and host macrophages.
在宿主巨噬细胞中存活是病原菌传播的一种有效策略。已发现嗜水气单胞菌能在鱼类巨噬细胞中存活，但其机制尚不清楚。本文研究了IcmF在嗜水气单胞菌于鱼类巨噬细胞中存活的作用及可能机制。首先，通过shRNA构建了稳定沉默菌株icmF-RNAi，RT-qPCR证实icmF的表达下调了94.42%。icmF-RNAi中Hcp、DotU和VgrG的表达也降低。野生型菌株的细胞内存活率为92.3%，而icmF-RNAi的存活率仅为20.58%。野生型菌株的逃逸率为20%，而icmF-RNAi的逃逸率仅为7.5%。进一步研究表明，icmF的表达可显著影响嗜水气单胞菌的黏附、生物膜形成、运动性和耐酸性，但即使在H₂O₂胁迫下对嗜水气单胞菌的生长也无显著影响。结果表明，嗜水气单胞菌的IcmF不仅作为一种结构蛋白参与细菌运动性、黏附及生物膜形成等与毒力相关的特性，还作为一种关键功能蛋白参与细菌与宿主巨噬细胞之间的相互作用。
