Pseudomonas expression of an oxygen sensing prolyl hydroxylase homologue regulates neutrophil host responses in vitro and in vivo.
Pseudomonas expression of an oxygen sensing prolyl hydroxylase homologue regulates neutrophil host responses in vitro and in vivo.
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DOI：
10.12688/wellcomeopenres.12871.1
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发表时间：
2017
影响因子：
--
通讯作者：
Walmsley SR
中科院分区：
文献类型：
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作者：
Dickinson RS;Murphy F;Doherty C;Williams S;Mirchandani A;Willson J;Scotti JS;Preston G;Schofield CJ;Whyte MKB;Walmsley SR
背景资料：假单胞菌适应于逃避先天性免疫应答，并且可以在相对组织缺氧的部位持续存在，包括囊性纤维化和支气管扩张患者的粘液堵塞的气道。这些细菌直接感知和响应局部氧可用性变化的能力部分取决于2-酮戊二酸加氧酶、假单胞菌脯氨酰羟化酶（PPHD）、其作用于延伸因子Tu（EF-Tu），并且与人缺氧诱导因子（HIF）脯氨酰羟化酶同源。我们报告PPHD表达调节中性粒细胞对急性假单胞菌感染的反应。 研究方法：用人中性粒细胞和PPHD缺陷型和野生型细菌和上清液进行体外共培养实验，通过流式细胞术测定活中性粒细胞计数。在气管内攻击后，在急性肺炎小鼠模型中测定PPHD缺陷型铜绿假单胞菌感染的体内后果。 结果如下：PPHD缺陷型细菌培养物的上清液含有更高浓度的吩嗪外毒素绿脓菌素，并且在体外诱导比野生型PAO 1上清液更大的中性粒细胞凋亡加速。与野生型PAO 1对照相比，用PPHD突变体体内感染导致中性粒细胞凋亡水平增加和感染控制受损，从感染PPHD缺陷型菌株的小鼠的肺中回收的铜绿假单胞菌数量更高，这导致感染PPHD缺陷型菌株的小鼠的死亡率总体增加。 结论：我们的数据表明，假单胞菌的脯氨酰羟化酶的表达影响宿主-病原体在体外和体内的相互作用的结果，证明了考虑宿主和病原体如何适应缺氧一起定义感染的结果的重要性。考虑到HIF脯氨酰羟化酶的抑制剂处于治疗贫血的后期试验中，并且PPHD和人HIF脯氨酰羟化酶的活性位点密切相关，因此该结果具有临床意义。
Background: Pseudomonas species are adapted to evade innate immune responses and can persist at sites of relative tissue hypoxia, including the mucus-plugged airways of patients with cystic fibrosis and bronchiectasis. The ability of these bacteria to directly sense and respond to changes in local oxygen availability is in part consequent upon expression of the 2-oxoglutarate oxygenase, Pseudomonas prolyl hydroxylase (PPHD), which acts on elongation factor Tu (EF-Tu), and is homologous with the human hypoxia inducible factor (HIF) prolyl hydroxylases. We report that PPHD expression regulates the neutrophil response to acute pseudomonal infection. Methods: In vitro co-culture experiments were performed with human neutrophils and PPHD-deficient and wild-type bacteria and supernatants, with viable neutrophil counts determined by flow cytometry. In vivo consequences of infection with PPHD deficient P. aeruginosa were determined in an acute pneumonia mouse model following intra-tracheal challenge. Results: Supernatants of PPHD-deficient bacterial cultures contained higher concentrations of the phenazine exotoxin pyocyanin and induced greater acceleration of neutrophil apoptosis than wild-type PAO1 supernatants in vitro. In vivo infection with PPHD mutants compared to wild-type PAO1 controls resulted in increased levels of neutrophil apoptosis and impaired control of infection, with higher numbers of P. aeruginosa recovered from the lungs of mice infected with the PPHD-deficient strain. This resulted in an overall increase in mortality in mice infected with the PPHD-deficient strain. Conclusions: Our data show that Pseudomonas expression of its prolyl hydroxylase influences the outcome of host-pathogen interactions in vitro and in vivo, demonstrating the importance of considering how both host and pathogen adaptations to hypoxia together define outcomes of infection. Given that inhibitors for the HIF prolyl hydroxylases are in late stage trials for the treatment of anaemia and that the active sites of PPHD and human HIF prolyl hydroxylases are closely related, the results are of current clinical interest.