The Two-Component System RstA/RstB Regulates Expression of Multiple Efflux Pumps and Influences Anaerobic Nitrate Respiration in Pseudomonas fluorescens.
The Two-Component System RstA/RstB Regulates Expression of Multiple Efflux Pumps and Influences Anaerobic Nitrate Respiration in Pseudomonas fluorescens.
复制标题
双组分系统 RstA/RstB 调节多个外排泵的表达并影响荧光假单胞菌中的厌氧硝酸盐呼吸。
DOI：
10.1128/msystems.00911-21
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发表时间：
2021-12-21
期刊：
影响因子：
6.4
通讯作者：
He YX
中科院分区：
文献类型：
--
作者：
Li DY;Han JT;Zhang MY;Yan X;Zhang N;Ge H;Wang Z;He YX
多药耐药（MDR）外排泵参与细菌对多种抗菌药物的内在耐药性。MDR外排泵的表达可以是组成型的，也可以是由各种环境信号瞬时诱导的，这些环境信号通常被细菌双组分系统（TCS）感知并中继到细菌类核，在类核中基因表达被调节以适应生态位。在这里，我们证明，RstA/RstB，TCS先前显示控制大肠杆菌中的酸诱导和生物膜相关基因，赋予耐多药荧光假单胞菌通过直接调节MDR外排泵EmhABC和MexCD-OprJ。此外，我们发现，在RstA的保守的Asp 52残基的磷酸化大大增强RstA-DNA相互作用，RstA/RstB的多药耐药的调节依赖于RstA Asp 52残基的磷酸化RstB。蛋白质组学分析表明，RstA/RstB还积极调节外排泵MexEF-OprN和参与厌氧硝酸盐呼吸和绿脓菌荧光素生物合成的酶。我们的研究结果表明，通过耦合多个外排泵的表达和厌氧硝酸盐呼吸，RstA/RstB可以发挥作用，以抵御由厌氧硝酸盐呼吸引起的亚硝化胁迫。微环境缺氧通常通过提高多药外排泵的表达来增加细菌的多药耐药性，但目前对其确切机制还不清楚。在这里，我们表明，双组分系统RstA/RstB不仅积极调节参与多药耐药的几个外排泵的表达，而且还促进参与厌氧硝酸盐呼吸和绿脓菌荧光素生物合成的酶的表达。这些结果表明，通过上调外排泵和绿脓菌荧光素生物合成相关酶的表达，RstA/RstB可以发挥作用，促进细菌耐缺氧，通过提供对亚硝化胁迫的保护。
Multidrug resistance (MDR) efflux pumps are involved in bacterial intrinsic resistance to multiple antimicrobials. Expression of MDR efflux pumps can be either constitutive or transiently induced by various environmental signals, which are typically perceived by bacterial two-component systems (TCSs) and relayed to the bacterial nucleoid, where gene expression is modulated for niche adaptation. Here, we demonstrate that RstA/RstB, a TCS previously shown to control acid-induced and biofilm-related genes in Escherichia coli, confers resistance to multiple antibiotics in Pseudomonas fluorescens by directly regulating the MDR efflux pumps EmhABC and MexCD-OprJ. Moreover, we show that phosphorylation of the conserved Asp52 residue in RstA greatly enhances RstA-DNA interaction, and regulation of the multidrug resistance by RstA/RstB is dependent on the phosphorylation of the RstA Asp52 residue by RstB. Proteome analysis reveals RstA/RstB also positively regulates the efflux pump MexEF-OprN and enzymes involved in anaerobic nitrate respiration and pyoverdine biosynthesis. Our results suggest that, by coupling the expression of multiple efflux pumps and anaerobic nitrate respiration, RstA/RstB could play a role in defense against nitrosative stress caused by anaerobic nitrate respiration. IMPORTANCE Microenvironmental hypoxia typically increases bacterial multidrug resistance by elevating expression of multidrug efflux pumps, but the precise mechanism is currently not well understood. Here, we showed that the two-component system RstA/RstB not only positively regulated expression of several efflux pumps involved in multidrug resistance, but also promoted expression of enzymes involved in anaerobic nitrate respiration and pyoverdine biosynthesis. These results suggested that, by upregulating expression of efflux pumps and pyoverdine biosynthesis-related enzymes, RstA/RstB could play a role in promoting bacterial tolerance to hypoxia by providing protection against nitrosative stress.