Cell Shape and Antibiotic Resistance Are Maintained by the Activity of Multiple FtsW and RodA Enzymes in Listeria monocytogenes
Cell Shape and Antibiotic Resistance Are Maintained by the Activity of Multiple FtsW and RodA Enzymes in Listeria monocytogenes
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DOI：
10.1128/mbio.01448-19
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发表时间：
2019-08
期刊：
影响因子：
6.4
通讯作者：
J. Rismondo;S. Halbedel;A. Gründling
中科院分区：
文献类型：
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作者：
J. Rismondo;S. Halbedel;A. Gründling
人类病原体单核细胞增生李斯特菌通常用高剂量的β-内酰胺类抗生素治疗，通常与庆大霉素联合使用。然而，这些抗生素仅对L.单核细胞增多症，需要免疫系统来清除感染。因此，免疫系统受损的个体有可能患上严重的李斯特菌感染，这在高达30%的病例中可能是致命的。发展新的策略来治疗李斯特菌感染是必要的。在这里，我们表明，表达的一些FtsW和RodA酶的L。单核细胞增多症是由β-内酰胺抗生素的存在诱导的，并且这些酶的组合缺乏使得细菌对这类抗生素更敏感。因此，开发抑制FtsW和RodA酶的活性或产生的抗微生物剂可能有助于改善李斯特菌感染的治疗，从而降低死亡率。摘要杆状细菌有两种肽聚糖合成方式：侧向合成和在细胞分裂位点合成。这两个过程是由两个大分子蛋白质复合物，延长体和分裂体。最近，已经表明，枯草芽孢杆菌RodA蛋白，其形成延长酶体的一部分，具有肽聚糖糖基转移酶活性。细胞分裂特异性的RodA同源物FtsW在分裂体中发挥类似的作用。人类病原体单核细胞增生李斯特菌携带编码多达6个FtsW/RodA同源物的基因;然而，它们的功能尚未被研究。缺失和耗竭菌株的分析导致鉴定了必需的细胞分裂特异性FtsW蛋白，FtsW 1。有趣的是，L。单核细胞增多症携带编码第二种FtsW蛋白FtsW 2的基因，当从诱导型启动子表达时，FtsW 2可以补偿FtsW 1的缺乏。L.单核细胞增多症还具有三个RodA同源物，RodA 1、RodA 2和RodA 3，并且它们的组合缺失是致命的。rodA 1 rodA 3双突变体的细胞更短，并且具有增加的抗生素和溶菌酶敏感性，这可能是由于细胞壁变弱。启动子活性测定的结果显示，在靶向青霉素结合蛋白的抗生素存在下诱导rodA 3和ftsW 2的表达。与此一致，rodA 3突变体对β-内酰胺抗生素头孢呋辛更敏感。有趣的是，RodA 3的过表达也导致头孢呋辛敏感性增加。我们的研究表明L.单核细胞增生基因编码多种功能性FtsW和RodA酶以产生其刚性细胞壁，并且它们的表达需要被严格调控以维持生长、细胞分裂和抗生素抗性。重要性人类病原体单核细胞增生李斯特菌通常用高剂量的β-内酰胺类抗生素治疗，通常与庆大霉素联合使用。然而，这些抗生素仅对L.单核细胞增多症，需要免疫系统来清除感染。因此，免疫系统受损的个体有可能患上严重的李斯特菌感染，这在高达30%的病例中可能是致命的。发展新的策略来治疗李斯特菌感染是必要的。在这里，我们表明，表达的一些FtsW和RodA酶的L。单核细胞增多症是由β-内酰胺抗生素的存在诱导的，并且这些酶的组合缺乏使得细菌对这类抗生素更敏感。因此，开发抑制FtsW和RodA酶的活性或产生的抗微生物剂可能有助于改善李斯特菌感染的治疗，从而降低死亡率。
The human pathogen Listeria monocytogenes is usually treated with high doses of β-lactam antibiotics, often combined with gentamicin. However, these antibiotics only act bacteriostatically on L. monocytogenes, and the immune system is needed to clear the infection. Therefore, individuals with a compromised immune system are at risk to develop a severe form of Listeria infection, which can be fatal in up to 30% of cases. The development of new strategies to treat Listeria infections is necessary. Here we show that the expression of some of the FtsW and RodA enzymes of L. monocytogenes is induced by the presence of β-lactam antibiotics, and the combined absence of these enzymes makes bacteria more susceptible to this class of antibiotics. The development of antimicrobial agents that inhibit the activity or production of FtsW and RodA enzymes might therefore help to improve the treatment of Listeria infections and thereby lead to a reduction in mortality. ABSTRACT Rod-shaped bacteria have two modes of peptidoglycan synthesis: lateral synthesis and synthesis at the cell division site. These two processes are controlled by two macromolecular protein complexes, the elongasome and divisome. Recently, it has been shown that the Bacillus subtilis RodA protein, which forms part of the elongasome, has peptidoglycan glycosyltransferase activity. The cell division-specific RodA homolog FtsW fulfils a similar role at the divisome. The human pathogen Listeria monocytogenes carries genes that encode up to six FtsW/RodA homologs; however, their functions have not yet been investigated. Analysis of deletion and depletion strains led to the identification of the essential cell division-specific FtsW protein, FtsW1. Interestingly, L. monocytogenes carries a gene that encodes a second FtsW protein, FtsW2, which can compensate for the lack of FtsW1, when expressed from an inducible promoter. L. monocytogenes also possesses three RodA homologs, RodA1, RodA2, and RodA3, and their combined absence is lethal. Cells of a rodA1 rodA3 double mutant are shorter and have increased antibiotic and lysozyme sensitivity, probably due to a weakened cell wall. Results from promoter activity assays revealed that expression of rodA3 and ftsW2 is induced in the presence of antibiotics targeting penicillin binding proteins. Consistent with this, a rodA3 mutant was more susceptible to the β-lactam antibiotic cefuroxime. Interestingly, overexpression of RodA3 also led to increased cefuroxime sensitivity. Our study highlights that L. monocytogenes genes encode a multitude of functional FtsW and RodA enzymes to produce its rigid cell wall and that their expression needs to be tightly regulated to maintain growth, cell division, and antibiotic resistance. IMPORTANCE The human pathogen Listeria monocytogenes is usually treated with high doses of β-lactam antibiotics, often combined with gentamicin. However, these antibiotics only act bacteriostatically on L. monocytogenes, and the immune system is needed to clear the infection. Therefore, individuals with a compromised immune system are at risk to develop a severe form of Listeria infection, which can be fatal in up to 30% of cases. The development of new strategies to treat Listeria infections is necessary. Here we show that the expression of some of the FtsW and RodA enzymes of L. monocytogenes is induced by the presence of β-lactam antibiotics, and the combined absence of these enzymes makes bacteria more susceptible to this class of antibiotics. The development of antimicrobial agents that inhibit the activity or production of FtsW and RodA enzymes might therefore help to improve the treatment of Listeria infections and thereby lead to a reduction in mortality.