The Vibrio cholerae RND efflux systems impact virulence factor production and adaptive responses via periplasmic sensor proteins.
The Vibrio cholerae RND efflux systems impact virulence factor production and adaptive responses via periplasmic sensor proteins.
复制标题
弧形霍乱RND外排系统通过周质传感器蛋白影响毒力因子的产生和适应性反应。
DOI：
10.1371/journal.ppat.1006804
复制
发表时间：
2018-01
期刊：
影响因子：
6.7
通讯作者：
Bina JE
中科院分区：
文献类型：
--
作者：
Bina XR;Howard MF;Taylor-Mulneix DL;Ante VM;Kunkle DE;Bina JE
耐药-增殖-分裂（RND）外排系统是革兰氏阴性菌中普遍存在的转运蛋白，对抗生素耐药性至关重要。RND外排系统也有助于独立于抗菌素耐药性的多种表型，但它们影响大多数表型的机制尚不清楚。这是霍乱弧菌的情况，其中RND系统在抗微生物剂抗性和毒力因子产生中起作用。在此，我们研究了RND流出和霍乱弧菌毒力之间的联系。RNA测序显示，RND流出的损失影响周质传感系统的激活状态，包括毒力调节因子ToxR。RND无效突变体中ToxR的激活导致LysR家族调节因子leuO的ToxR依赖性转录。leuO转录的增加导致ToxR毒力调节子的抑制和毒力因子的产生减弱。与此相一致，leuO缺失恢复了RND无效突变体中的毒力因子生产，但不能恢复其定植婴儿小鼠的能力;这表明RND外排对定植的毒力因子生产具有上位性。在RND无效突变体中，ToxR的周质感测结构域是诱导leuO转录所需的，这表明ToxR响应于周质中积累的代谢物。我们的研究结果表明，ToxR抑制毒力因子的生产，在响应代谢物，通常从细胞中流出的RND转运蛋白。我们提出，受损的RND流出导致周质代谢物积累，然后激活周质传感器，包括ToxR和双组分调节系统，以启动适应性反应的表达。属于RND超家族的多药外排系统有助于革兰氏阴性菌中多种表型的表达，但将RND外排与这些表型联系起来的机制尚不清楚。在此，我们提供的证据表明，霍乱弧菌RND系统通过挤压细胞代谢物影响全局转录模式。RND流出的抑制导致细胞代谢物在细胞内积累，在细胞内它们刺激周质传感器，包括毒力调节因子ToxR。然后，传感器蛋白启动转录反应的表达，在霍乱弧菌中包括ToxR介导的毒力因子产生的抑制。这项研究揭示了革兰氏阴性细菌中RND系统的天然功能，并提出了RND介导的外排在环境感知和适应中的新范式。
Resistance-nodulation-division (RND) efflux systems are ubiquitous transporters in Gram-negative bacteria that are essential for antibiotic resistance. The RND efflux systems also contribute to diverse phenotypes independent of antimicrobial resistance, but the mechanism by which they affect most of these phenotypes is unclear. This is the case in Vibrio cholerae where the RND systems function in antimicrobial resistance and virulence factor production. Herein, we investigated the linkage between RND efflux and V. cholerae virulence. RNA sequencing revealed that the loss of RND efflux affected the activation state of periplasmic sensing systems including the virulence regulator ToxR. Activation of ToxR in an RND null mutant resulted in ToxR-dependent transcription of the LysR-family regulator leuO. Increased leuO transcription resulted in the repression of the ToxR virulence regulon and attenuated virulence factor production. Consistent with this, leuO deletion restored virulence factor production in an RND-null mutant, but not its ability to colonize infant mice; suggesting that RND efflux was epistatic to virulence factor production for colonization. The periplasmic sensing domain of ToxR was required for the induction of leuO transcription in the RND null mutant, suggesting that ToxR responded to metabolites that accumulated in the periplasm. Our results suggest that ToxR represses virulence factor production in response to metabolites that are normally effluxed from the cell by the RND transporters. We propose that impaired RND efflux results in periplasmic metabolite accumulation, which then activates periplasmic sensors including ToxR and two-component regulatory systems to initiate the expression of adaptive responses. Multidrug efflux systems belonging to the RND superfamily contribute to the expression of diverse phenotypes in Gram-negative bacteria, but the mechanisms linking RND efflux to these phenotypes is unclear. Herein, we provide evidence suggesting that the V. cholerae RND systems influence global transcription patterns by extruding cell metabolites. Inhibition of RND efflux causes cell metabolites to accumulate intracellularly where they stimulate periplasmic sensors including the virulence regulator ToxR. The sensor proteins then initiate the expression of transcriptional responses, which in V. cholerae includes ToxR-mediated repression of virulence factor production. This study sheds light on the native functions of RND systems in Gram-negative bacteria and suggests a new paradigm for RND-mediated efflux in environmental sensing and adaptation.
登录
查看更多内容
影响因子：
5.2
作者：
Bina, Xiaowen R.;Philippart, Julie A.;Bina, James E.
通讯作者：
Bina, James E.
影响因子：
3.6
作者：
Kovacikova, G;Skorupski, K
通讯作者：
Skorupski, K
影响因子：
3.2
作者：
LINN, T;STPIERRE, R
通讯作者：
STPIERRE, R
影响因子：
2.8
作者：
Ante, Vanessa M.;Bina, X. Renee;Bina, James E.
通讯作者：
Bina, James E.
影响因子：
4.8
作者：
Cai, SJ;Inouye, M
通讯作者：
Inouye, M