The Gac/Rsm and cyclic-di-GMP signalling networks coordinately regulate iron uptake in Pseudomonas aeruginosa
The Gac/Rsm and cyclic-di-GMP signalling networks coordinately regulate iron uptake in Pseudomonas aeruginosa
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DOI：
10.1111/1462-2920.12164
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发表时间：
2014-03-01
影响因子：
5.1
通讯作者：
Imperi, Francesco
中科院分区：
文献类型：
--
作者：
Frangipani, Emanuela;Visaggio, Daniela;Imperi, Francesco
铜绿假单胞菌是一种多功能的细菌病原体，能够占据不同的生态位。为了科普铁限制，铜绿假单胞菌分泌两种铁载体，绿脓菌荧光素和绿脓菌螯铁蛋白，其将铁递送至细胞的能力对于生物膜形成和致病性至关重要。在这项研究中，我们描述了铁的吸收和Gac/RSM系统，一个保守的信号转导途径的铜绿假单胞菌，控制生产的胞外产物和毒力因子，以及从嗜铁蛋白生物膜的生活方式的开关之间的联系。我们已经观察到铜绿假单胞菌中绿脓菌荧光素和绿脓菌螯铁蛋白的产生强烈依赖于Gac/Rsm途径的激活状态，其以不涉及铁摄取调节因子（Fur）表达的调节的方式在转录水平上控制铁载体调节和生物合成基因。Gac/Rsm介导的铁摄取基因调控似乎在不同铜绿假单胞菌菌株中是保守的。进一步的实验导致建议，GAC/RSM系统调节铁载体的生产，通过调节细胞内水平的第二信使c-di-GMP，表明c-di-GMP和GAC/RSM的生物膜形成所必需的监管网络也可以协调控制铁的吸收在铜绿假单胞菌。
Pseudomonas aeruginosa is a versatile bacterial pathogen capable of occupying diverse ecological niches. To cope with iron limitation, P.aeruginosa secretes two siderophores, pyoverdine and pyochelin, whose ability to deliver iron to the cell is crucial for biofilm formation and pathogenicity. In this study, we describe a link between iron uptake and the Gac/Rsm system, a conserved signal transducing pathway of P.aeruginosa that controls the production of extracellular products and virulence factors, as well as the switch from planktonic to biofilm lifestyle. We have observed that pyoverdine and pyochelin production in P.aeruginosa is strongly dependent on the activation state of the Gac/Rsm pathway, which controls siderophore regulatory and biosynthetic genes at the transcriptional level, in a manner that does not involve regulation of ferric uptake regulator (Fur) expression. Gac/Rsm-mediated regulation of iron uptake genes appears to be conserved in different P.aeruginosa strains. Further experiments led to propose that the Gac/Rsm system regulates siderophore production through modulation of the intracellular levels of the second messenger c-di-GMP, indicating that the c-di-GMP and the Gac/Rsm regulatory networks essential for biofilm formation can also coordinately control iron uptake in P.aeruginosa.