West China School of Public Health and West China Fourth Hospital, Sichuan University, 16#, Section 3, Ren Min Nan Road, Chengdu, 610041, Sichuan, People's Republic of China.
Shimadzu (China) Co., Ltd., Chengdu, 610063, Sichuan, People's Republic of China.
Metabolomics. 2022 Nov 15;18(11):93. doi: 10.1007/s11306-022-01946-z.
Previous reports revealed the role played by Salmonella PhoP-PhoQ system in virulence activation, antimicrobial tolerance and intracellular survival, the impact of PhoP-PhoQ on cell metabolism has been less extensively described.
The aim of this study is to address whether and how the PhoP-PhoQ system affects the cell metabolism of Salmonella.
We constructed a Salmonella phoP deletion mutant strain TT-81 (PhoP-OFF), a Salmonella PhoP constitutively expressed strain TT-82 (PhoP-ON) and a wild-type Salmonella PhoP strain TT-80 (PhoP-N), using P22-mediated generalized transduction or λ Red-mediated targeted mutagenesis. We then measured the in vitro growth kinetics of all test strains and determined their metabolomic and transcriptomic profiles using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) and RNA-seq technique, respectively.
Low-Mg conditions impaired the growth of the phoP deletion mutant strain TT-81 (PhoP-OFF) dramatically. 42 metabolites in the wild-type PhoP strain TT-80 (PhoP-N) and 28 metabolites in the PhoP constitutively expressed strain TT-82 (PhoP-ON) changed by the absence of phoP. In contrast, the level of 19 compounds in TT-80 (PhoP-N) changed comparing to the PhoP constitutively expressed strain TT-82 (PhoP-N). The mRNA level of 95 genes in TT-80 (PhoP-N) changed when phoP was disrupted, wherein 78 genes downregulated and 17 genes upregulated. 106 genes were determined to be differentially expressed between TT-81 (PhoP-OFF) and TT-82 (PhoP-ON). While only 16 genes were found to differentially expressed between TT-82 (PhoP-ON) and TT-80 (PhoP-N).
Our findings confirmed the impact of PhoP-PhoQ system on lipopolysaccharide (LPS) modification, energy metabolism, and the biosynthesis or transport of amino acids. Most importantly, we demonstrated that the turnover of a given metabolite could respond differentially to the level of phoP. Taken together, the present study provided new insights into the adaptation of Salmonella to the host environment and helped to characterize the impact of the PhoP-PhoQ system on the cell metabolism.
先前的报告揭示了沙门氏菌 PhoP-PhoQ 系统在毒力激活、抗菌药物耐受和细胞内存活中的作用，PhoP-PhoQ 对细胞代谢的影响尚未得到广泛描述。
本研究旨在探讨 PhoP-PhoQ 系统是否以及如何影响沙门氏菌的细胞代谢。
我们使用 P22 介导的普遍转导或 λ Red 介导的靶向突变技术，构建了沙门氏菌 phoP 缺失突变菌株 TT-81（PhoP-OFF）、沙门氏菌 PhoP 组成型表达菌株 TT-82（PhoP-ON）和野生型沙门氏菌 PhoP 菌株 TT-80（PhoP-N）。然后，我们使用气相色谱-串联质谱（GC-MS/MS）和 RNA-seq 技术分别测量所有测试菌株的体外生长动力学，并确定它们的代谢组学和转录组学图谱。
低镁条件显著损害了 phoP 缺失突变菌株 TT-81（PhoP-OFF）的生长。野生型 PhoP 菌株 TT-80（PhoP-N）中有 42 种代谢物和 PhoP 组成型表达菌株 TT-82（PhoP-ON）中有 28 种代谢物因缺失 phoP 而发生变化。相比之下，与 PhoP 组成型表达菌株 TT-82（PhoP-ON）相比，TT-80（PhoP-N）中有 19 种化合物的水平发生了变化。当 phoP 被破坏时，TT-80（PhoP-N）中有 95 个基因的 mRNA 水平发生了变化，其中 78 个基因下调，17 个基因上调。TT-81（PhoP-OFF）和 TT-82（PhoP-ON）之间有 106 个基因被确定为差异表达。而 TT-82（PhoP-ON）和 TT-80（PhoP-N）之间只有 16 个基因差异表达。
我们的研究结果证实了 PhoP-PhoQ 系统对脂多糖（LPS）修饰、能量代谢以及氨基酸的生物合成或运输的影响。最重要的是，我们证明了给定代谢物的周转率可以对 phoP 的水平做出不同的反应。总之，本研究为沙门氏菌对宿主环境的适应提供了新的见解，并有助于描述 PhoP-PhoQ 系统对细胞代谢的影响。
