Pseudomonas aeruginosa PA80 is a cystic fibrosis isolate deficient in RhlRI quorum sensing.
Pseudomonas aeruginosa PA80 is a cystic fibrosis isolate deficient in RhlRI quorum sensing.
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DOI：
10.1038/s41598-021-85100-0
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发表时间：
2021-03-11
影响因子：
4.6
通讯作者：
Dooley JSG
中科院分区：
文献类型：
--
作者：
Ahmed SAKS;Rudden M;Elias SM;Smyth TJ;Marchant R;Banat IM;Dooley JSG
铜绿假单胞菌利用群体感应（QS）来调节几种毒力因子的表达，使其能够建立严重的感染。铜绿假单胞菌中的QS系统是复杂的，错综复杂的，并且由两个主要的N-酰基-高丝氨酸内酯回路LasRI和RhlRI主导。这两个QS系统以分层方式工作，LasRI在顶部，直接调节RhlRI。这些QS回路共同调节铜绿假单胞菌中的几种毒力相关基因、代谢物和酶。奇怪的是，LasR突变体经常从慢性铜绿假单胞菌感染中分离出来，通常在囊性纤维化（CF）患者中。这表明铜绿假单胞菌可以经历显著的进化病理适应，以持续长期慢性感染。相比之下，RhlRI系统中的突变不太常见。在这里，我们已经从CF患者中分离出铜绿假单胞菌的临床菌株，其已经完全删除了转录调节因子RhlR。全基因组测序显示，PA 80中的rhIR基因座缺失，同时在毒力因子（包括蛋白酶lasA和鼠李糖脂rhlA、rhlB、rhlC）中存在一些非同义突变。重要的是，我们在LasRI QS系统中没有观察到任何突变。PA 80似乎不具有通常与几个标志性病理适应性基因相关的突变的积累（即，mexT、mucA、algR、rpoN、exsS、ampR）。全基因组比较显示，铜绿假单胞菌菌株PA 80与高毒力利物浦流行株（LES）LESB 58密切相关。PA 80还含有几个编码与LESB 58同源的毒力和/或抗性决定簇的基因组岛（GI）。为了进一步了解这些突变在PA 80 QS调控和毒力相关基因中的作用，我们比较了基因转录表达和表型效应与遗传参考菌株PAO 1中的同基因突变体。在PAO 1中，我们发现rhlR的缺失对广泛的毒力相关因子的表达具有更显著的影响，而不是lasR的缺失。在PA 80中，没有QS调节基因表达，我们认为这是由于rhlR的缺失和rhlI的突变使RhlRI QS系统失活。该研究表明，LasRI系统的失活不影响RhlRI调节的毒力因子。PA 80通过靶向RhlRI系统绕过了在LasR中观察到的常见病理适应性突变。这表明RhlRI是慢性CF患者中铜绿假单胞菌长期持续存在的重要靶标。这在针对QS系统进行治疗干预方面提出了重要问题。
Pseudomonas aeruginosa uses quorum sensing (QS) to modulate the expression of several virulence factors that enable it to establish severe infections. The QS system in P. aeruginosa is complex, intricate and is dominated by two main N-acyl-homoserine lactone circuits, LasRI and RhlRI. These two QS systems work in a hierarchical fashion with LasRI at the top, directly regulating RhlRI. Together these QS circuits regulate several virulence associated genes, metabolites, and enzymes in P. aeruginosa. Paradoxically, LasR mutants are frequently isolated from chronic P. aeruginosa infections, typically among cystic fibrosis (CF) patients. This suggests P. aeruginosa can undergo significant evolutionary pathoadaptation to persist in long term chronic infections. In contrast, mutations in the RhlRI system are less common. Here, we have isolated a clinical strain of P. aeruginosa from a CF patient that has deleted the transcriptional regulator RhlR entirely. Whole genome sequencing shows the rhlR locus is deleted in PA80 alongside a few non-synonymous mutations in virulence factors including protease lasA and rhamnolipid rhlA, rhlB, rhlC. Importantly we did not observe any mutations in the LasRI QS system. PA80 does not appear to have an accumulation of mutations typically associated with several hallmark pathoadaptive genes (i.e., mexT, mucA, algR, rpoN, exsS, ampR). Whole genome comparisons show that P. aeruginosa strain PA80 is closely related to the hypervirulent Liverpool epidemic strain (LES) LESB58. PA80 also contains several genomic islands (GI’s) encoding virulence and/or resistance determinants homologous to LESB58. To further understand the effect of these mutations in PA80 QS regulatory and virulence associated genes, we compared transcriptional expression of genes and phenotypic effects with isogenic mutants in the genetic reference strain PAO1. In PAO1, we show that deletion of rhlR has a much more significant impact on the expression of a wide range of virulence associated factors rather than deletion of lasR. In PA80, no QS regulatory genes were expressed, which we attribute to the inactivation of the RhlRI QS system by deletion of rhlR and mutation of rhlI. This study demonstrates that inactivation of the LasRI system does not impact RhlRI regulated virulence factors. PA80 has bypassed the common pathoadaptive mutations observed in LasR by targeting the RhlRI system. This suggests that RhlRI is a significant target for the long-term persistence of P. aeruginosa in chronic CF patients. This raises important questions in targeting QS systems for therapeutic interventions.
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影响因子：
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作者：
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影响因子：
11.1
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