Pseudomonas aeruginosa pili and flagella mediate distinct binding and signaling events at the apical and basolateral surface of airway epithelium.
Pseudomonas aeruginosa pili and flagella mediate distinct binding and signaling events at the apical and basolateral surface of airway epithelium.
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DOI：
10.1371/journal.ppat.1002616
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发表时间：
2012
期刊：
影响因子：
6.7
通讯作者：
Engel JN
中科院分区：
文献类型：
--
作者：
Bucior I;Pielage JF;Engel JN
铜绿假单胞菌是人类重要的机会致病菌，它利用许多因素来初始附着于宿主，这是建立细菌感染所需的事件。在本文中，我们严格探讨了两个主要的细菌粘附素，IV型皮利（TFP）和鞭毛，在细菌粘附不同的主机受体在顶端（AP）和基底侧（BL）极化肺上皮细胞的表面和诱导随后的主机信号和致病事件的作用。使用缺乏鞭毛的铜绿假单胞菌的同基因突变体或利用涂覆有纯化的Tfp的珠粒，我们确定Tfp对于在极化上皮的AP表面处最大化结合宿主N-聚糖是必要的且足够的。相比之下，利用缺乏Tfp的铜绿假单胞菌同基因突变体或使用涂覆有纯化鞭毛的珠粒的实验证明，鞭毛对于在极化上皮的BL表面处与硫酸乙酰肝素蛋白聚糖（HSPG）的硫酸乙酰肝素（HS）链的最大结合是必要的且足够的。使用两种不同的无细胞系统，我们证明，TFP包被的珠显示出最高的结合亲和力，复杂的N-聚糖链包被到塑料板上，并优先聚集与N-聚糖包被的珠，但不与单糖或HS。相比之下，鞭毛包被的珠粒优先与HS或HSPG结合或聚集，但表现出很少与N-聚糖结合。我们进一步表明，Tfp介导的结合宿主N-聚糖的结果激活磷脂酰肌醇3-激酶（PI 3 K）/Akt途径和细菌进入AP表面。在BL表面，鞭毛介导的与HS的结合激活表皮生长因子受体（EGFR）、衔接蛋白Shc和PI 3 K/Akt，并诱导细菌进入。值得注意的是，单独的鞭毛包被的珠子可以激活EGFR和Shc。总之，这项工作为铜绿假单胞菌和肺上皮之间复杂的相互作用提供了新的见解，这可能有助于开发铜绿假单胞菌感染的新型治疗方法。 铜绿假单胞菌是一种致病力最强的院内机会致病菌，可引起多种危及生命的感染。抗生素耐药性普遍存在，归因死亡率仍接近50%。与上皮细胞的复合物结合是这种强效病原体释放其毒力因子的关键第一步。极化上皮具有不同的顶端（AP）和基底外侧（BL）表面，由不同的糖基化分子组成，铜绿假单胞菌可能采用不同的粘附素与这些受体结合。使用同基因突变体以及在体外无细胞测定，我们证明，细菌IV型皮利是必要的，足以介导AP与N-聚糖的相互作用，而细菌鞭毛与硫酸乙酰肝素链的蛋白聚糖的BL表面上。这些相互作用诱导特定的宿主信号传导途径，导致随后的致病事件，如细菌进入宿主上皮。此外，我们表明，鞭毛本身就足以激活表皮生长因子受体和衔接蛋白的BL表面上。这些研究揭示了关于铜绿假单胞菌与宿主的多种相互作用中的关键参与者的新信息，并为阻断建立铜绿假单胞菌感染所必需的早期结合步骤提供了有吸引力的靶点。
Pseudomonas aeruginosa, an important opportunistic pathogen of man, exploits numerous factors for initial attachment to the host, an event required to establish bacterial infection. In this paper, we rigorously explore the role of two major bacterial adhesins, type IV pili (Tfp) and flagella, in bacterial adherence to distinct host receptors at the apical (AP) and basolateral (BL) surfaces of polarized lung epithelial cells and induction of subsequent host signaling and pathogenic events. Using an isogenic mutant of P. aeruginosa that lacks flagella or utilizing beads coated with purified Tfp, we establish that Tfp are necessary and sufficient for maximal binding to host N-glycans at the AP surface of polarized epithelium. In contrast, experiments utilizing a P. aeruginosa isogenic mutant that lacks Tfp or using beads coated with purified flagella demonstrate that flagella are necessary and sufficient for maximal binding to heparan sulfate (HS) chains of heparan sulfate proteoglycans (HSPGs) at the BL surface of polarized epithelium. Using two different cell-free systems, we demonstrate that Tfp-coated beads show highest binding affinity to complex N-glycan chains coated onto plastic plates and preferentially aggregate with beads coated with N-glycans, but not with single sugars or HS. In contrast, flagella-coated beads bind to or aggregate preferentially with HS or HSPGs, but demonstrate little binding to N-glycans. We further show that Tfp-mediated binding to host N-glycans results in activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway and bacterial entry at the AP surface. At the BL surface, flagella-mediated binding to HS activates the epidermal growth factor receptor (EGFR), adaptor protein Shc, and PI3K/Akt, and induces bacterial entry. Remarkably, flagella-coated beads alone can activate EGFR and Shc. Together, this work provides new insights into the intricate interactions between P. aeruginosa and lung epithelium that may be potentially useful in the development of novel treatments for P. aeruginosa infections. Pseudomonas aeruginosa is one of the most virulent nosocomial opportunistic pathogens that is associated with a broad spectrum of life-threatening infections. Antibiotic resistance is widespread and attributable mortality remains near 50%. Complex binding to epithelial cells is a key first step for this potent pathogen to unleash its armamentarium of virulence factors. Polarized epithelium has distinct apical (AP) and basolateral (BL) surface, composed of different glycosylated molecules, and P. aeruginosa can potentially employ different adhesins to bind to these receptors. Using isogenic mutants as well as in vitro cell-free assays, we demonstrate that bacterial type IV pili are necessary and sufficient to mediate AP interactions with N-glycans whereas bacterial flagella interact with heparan sulfate chains of proteoglycans on the BL surface. These interactions induce specific host signaling pathways that lead to subsequent pathogenic events, such as bacterial entry into host epithelium. Moreover, we show that flagella alone are sufficient to activate the epidermal growth factor receptor and the adaptor protein on the BL surface. These studies reveal new information about key players in the versatile interactions of P. aeruginosa with the host and provide appealing targets for blocking early binding steps essential for establishment of P. aeruginosa infections.
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影响因子：
3.7
作者：
Gao N;Kumar A;Jyot J;Yu FS
通讯作者：
Yu FS
影响因子：
3.1
作者：
Bucior, Iwona;Mostov, Keith;Engel, Joanne N.
通讯作者：
Engel, Joanne N.
影响因子：
3.1
作者：
Gerçeker, AA;Zaidi, T;Pier, GB
通讯作者：
Pier, GB
影响因子：
2.6
作者：
Abraham, SN;Duncan, MJ;Zaas, D
通讯作者：
Zaas, D
DOI：
10.1083/jcb.200309005
发表时间：
2004-05-24
期刊：
The Journal of cell biology
影响因子：
--
作者：
Bucior I;Scheuring S;Engel A;Burger MM
通讯作者：
Burger MM