Response of Pseudomonas aeruginosa to the Innate Immune System-Derived Oxidants Hypochlorous Acid and Hypothiocyanous Acid.
Response of Pseudomonas aeruginosa to the Innate Immune System-Derived Oxidants Hypochlorous Acid and Hypothiocyanous Acid.
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DOI：
10.1128/jb.00300-20
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发表时间：
2020-12-18
影响因子：
3.2
通讯作者：
Williams HD
中科院分区：
文献类型：
--
作者：
Farrant KV;Spiga L;Davies JC;Williams HD
细菌病原体铜绿假单胞菌在免疫功能低下的宿主中引起毁灭性的感染，包括囊性纤维化患者的慢性肺部感染。为了对抗感染，宿主的免疫系统产生抗微生物氧化剂次氯酸（HOCl）和次硫氰酸（HOSCN）。关于铜绿假单胞菌如何对这些氧化剂的攻击作出反应并存活下来，人们知之甚少。为了解决这个问题，我们采用了两种方法：突变筛选和转录研究。我们确定了铜绿假单胞菌的转录调节因子RclR，它对HOCl和HOSCN胁迫有特异性反应，并且对抵抗这两种氧化剂至关重要。我们发现了铜绿假单胞菌对这些氧化剂的转录反应与致病性相关的生理过程之间的联系，包括抗生素耐药性和3型分泌系统。铜绿假单胞菌是一种重要的医院病原体，与囊性纤维化（CF）的肺部感染有关。一旦建立，铜绿假单胞菌感染持续存在，并且很少被根除，尽管宿主免疫细胞产生抗微生物氧化剂，包括次氯酸（HOCl）和次硫氰酸（HOSCN）。关于铜绿假单胞菌如何感知、响应和保护自己免受HOCl和HOSCN的侵害，以及这些反应对其成功成为CF病原体的贡献，目前的知识有限。为了研究铜绿假单胞菌对这些氧化剂的反应，我们筛选了707个转座子突变体，这些转座子突变体在暴露于HOCl后发生了调节基因突变，以改变生长。我们确定了抗生素耐药性、蛋氨酸生物合成、分解代谢抑制和PA14_07340的调节因子，这是大肠杆菌HOCl传感器RclR的同源物（30%相同），它们是抵御HOCl所必需的。我们已经证明，RclR （PA14_07340）对HOCl和HOSCN胁迫具有特异性保护作用，并通过上调一种推测的过氧化物还氧蛋白rclX （PA14_07355）的表达来响应这两种氧化剂。转录分析显示，虽然对HOCl（231个基因上调）和HOSCN（105个基因上调）的反应具有特异性，但存在相当大的重叠，两种氧化剂上调了74个基因。这些基因包括编码3型分泌系统、硫和牛磺酸运输以及MexEF-OprN外排泵的基因。RclR协调了对这两种氧化剂的部分反应，包括花青素生物合成基因的上调，以及HOSCN存在时伴侣基因的下调。这些数据表明，P. aeruginosa对HOCl和HOSCN的反应是多方面的，其中RclR起着重要作用。细菌病原体铜绿假单胞菌在免疫功能低下的宿主中引起毁灭性的感染，包括囊性纤维化患者的慢性肺部感染。为了对抗感染，宿主的免疫系统产生抗微生物氧化剂次氯酸（HOCl）和次硫氰酸（HOSCN）。关于铜绿假单胞菌如何对这些氧化剂的攻击作出反应并存活下来，人们知之甚少。为了解决这个问题，我们采用了两种方法：突变筛选和转录研究。我们确定了铜绿假单胞菌的转录调节因子RclR，它对HOCl和HOSCN胁迫有特异性反应，并且对抵抗这两种氧化剂至关重要。我们发现了铜绿假单胞菌对这些氧化剂的转录反应与致病性相关的生理过程之间的联系，包括抗生素耐药性和3型分泌系统。
The bacterial pathogen Pseudomonas aeruginosa causes devastating infections in immunocompromised hosts, including chronic lung infections in cystic fibrosis patients. To combat infection, the host’s immune system produces the antimicrobial oxidants hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). Little is known about how P. aeruginosa responds to and survives attack from these oxidants. To address this, we carried out two approaches: a mutant screen and transcriptional study. We identified the P. aeruginosa transcriptional regulator, RclR, which responds specifically to HOCl and HOSCN stress and is essential for protection against both oxidants. We uncovered a link between the P. aeruginosa transcriptional response to these oxidants and physiological processes associated with pathogenicity, including antibiotic resistance and the type 3 secretion system. Pseudomonas aeruginosa is a significant nosocomial pathogen and is associated with lung infections in cystic fibrosis (CF). Once established, P. aeruginosa infections persist and are rarely eradicated despite host immune cells producing antimicrobial oxidants, including hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). There is limited knowledge as to how P. aeruginosa senses, responds to, and protects itself against HOCl and HOSCN and the contribution of such responses to its success as a CF pathogen. To investigate the P. aeruginosa response to these oxidants, we screened 707 transposon mutants, with mutations in regulatory genes, for altered growth following HOCl exposure. We identified regulators of antibiotic resistance, methionine biosynthesis, catabolite repression, and PA14_07340, the homologue of the Escherichia coli HOCl-sensor RclR (30% identical), which are required for protection against HOCl. We have shown that RclR (PA14_07340) protects specifically against HOCl and HOSCN stress and responds to both oxidants by upregulating the expression of a putative peroxiredoxin, rclX (PA14_07355). Transcriptional analysis revealed that while there was specificity in the response to HOCl (231 genes upregulated) and HOSCN (105 genes upregulated), there was considerable overlap, with 74 genes upregulated by both oxidants. These included genes encoding the type 3 secretion system, sulfur and taurine transport, and the MexEF-OprN efflux pump. RclR coordinates part of the response to both oxidants, including upregulation of pyocyanin biosynthesis genes, and, in the presence of HOSCN, downregulation of chaperone genes. These data indicate that the P. aeruginosa response to HOCl and HOSCN is multifaceted, with RclR playing an essential role. IMPORTANCE The bacterial pathogen Pseudomonas aeruginosa causes devastating infections in immunocompromised hosts, including chronic lung infections in cystic fibrosis patients. To combat infection, the host’s immune system produces the antimicrobial oxidants hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). Little is known about how P. aeruginosa responds to and survives attack from these oxidants. To address this, we carried out two approaches: a mutant screen and transcriptional study. We identified the P. aeruginosa transcriptional regulator, RclR, which responds specifically to HOCl and HOSCN stress and is essential for protection against both oxidants. We uncovered a link between the P. aeruginosa transcriptional response to these oxidants and physiological processes associated with pathogenicity, including antibiotic resistance and the type 3 secretion system.