Kim Seongok, Hwang Hyelyeon, Kim Kwang-Pyo, Yoon Hyunjin, Kang Dong-Hyun, Ryu Sangryeol
Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, Seoul, South Korea.
Department of Food Science and Technology, College of Agriculture and Life Sciences, Chonbuk National University, Jeonju, South Korea.
Infect Immun. 2015 May;83(5):2089-98. doi: 10.1128/IAI.03161-14. Epub 2015 Mar 9.
Cronobacter spp. are opportunistic pathogens that cause neonatal meningitis and sepsis with high mortality in neonates. Despite the peril associated with Cronobacter infection, the mechanisms of pathogenesis are still being unraveled. Hfq, which is known as an RNA chaperone, participates in the interaction with bacterial small RNAs (sRNAs) to regulate posttranscriptionally the expression of various genes. Recent studies have demonstrated that Hfq contributes to the pathogenesis of numerous species of bacteria, and its roles are varied between bacterial species. Here, we tried to elucidate the role of Hfq in C. sakazakii virulence. In the absence of hfq, C. sakazakii was highly attenuated in dissemination in vivo, showed defects in invasion (3-fold) into animal cells and survival (10(3)-fold) within host cells, and exhibited low resistance to hydrogen peroxide (10(2)-fold). Remarkably, the loss of hfq led to hypermotility on soft agar, which is contrary to what has been observed in other pathogenic bacteria. The hyperflagellated bacteria were likely to be attributable to the increased transcription of genes associated with flagellar biosynthesis in a strain lacking hfq. Together, these data strongly suggest that hfq plays important roles in the virulence of C. sakazakii by participating in the regulation of multiple genes.
阪崎肠杆菌属是机会致病菌，可导致新生儿脑膜炎和败血症，在新生儿中死亡率很高。尽管阪崎肠杆菌感染存在风险，但其致病机制仍在研究之中。Hfq作为一种RNA伴侣，参与与细菌小RNA（sRNA）的相互作用，从而在转录后水平调控各种基因的表达。最近的研究表明，Hfq有助于多种细菌的致病过程，且其在不同细菌种类中的作用各不相同。在此，我们试图阐明Hfq在阪崎肠杆菌毒力中的作用。在缺乏hfq的情况下，阪崎肠杆菌在体内的扩散能力大幅减弱，侵入动物细胞的能力（降低3倍）和在宿主细胞内的存活能力（降低10³倍）出现缺陷，并且对过氧化氢的抗性较低（降低10²倍）。值得注意的是，hfq的缺失导致在软琼脂上的运动性增强，这与在其他病原菌中观察到的情况相反。鞭毛增多的细菌可能归因于在缺乏hfq的菌株中与鞭毛生物合成相关基因的转录增加。总之，这些数据强烈表明hfq通过参与多个基因的调控在阪崎肠杆菌的毒力中发挥重要作用。
