A streptococcal Fic domain-containing protein disrupts blood-brain barrier integrity by activating moesin in endothelial cells
A streptococcal Fic domain-containing protein disrupts blood-brain barrier integrity by activating moesin in endothelial cells
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链球菌 Fic 结构域蛋白通过激活内皮细胞中的 moesin 破坏血脑屏障完整性
DOI：
10.1371/journal.ppat.1007737
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发表时间：
2019-05-01
期刊：
影响因子：
6.7
通讯作者：
Waldor, Matthew K.
中科院分区：
文献类型：
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作者：
Ma, Zhe;Peng, Jie;Waldor, Matthew K.
马链球菌动物寄生虫（SEZ）是一种能够引起人类脑膜炎的人畜共患病原体。病原体穿越血脑屏障（BBB）的机制尚不完全清楚。在这里，我们研究了一种新发现的含Fic结构域的蛋白BifA在SEZ毒力中的作用。SEZ需要BifA才能穿过BBB并在小鼠中引起脑膜炎。BifA还增强了SEZ跨人脑微血管内皮细胞（hBMEC）单层的易位。纯化的BifA或其含有Fic结构域的C-末端单独能够进入hBMEC，导致单层屏障完整性的破坏。基于SILAC的蛋白质组学筛选揭示BifA结合膜突蛋白。BifA的Fic结构域是其与宿主细胞细胞骨架过程的这种调节剂结合所必需的。BifA处理hBMEC导致膜突蛋白磷酸化和下游RhoA活化。抑制hBMEC单层中的膜突蛋白激活或膜突蛋白耗尽废除了BifA介导的屏障通透性增加和SEZ跨单层易位的能力。因此，膜突蛋白的BifA活化似乎构成了SEZ破坏内皮单层完整性以穿透BBB的关键机制。
Streptococcus equi subsp. zooepidemicus (SEZ) is a zoonotic pathogen capable of causing meningitis in humans. The mechanisms that enable pathogens to traverse the blood-brain barrier (BBB) are incompletely understood. Here, we investigated the role of a newly identified Fic domain-containing protein, BifA, in SEZ virulence. BifA was required for SEZ to cross the BBB and to cause meningitis in mice. BifA also enhanced SEZ translocation across human Brain Microvascular Endothelial Cell (hBMEC) monolayers. Purified BifA or its Fic domain-containing C-terminus alone were able to enter into hBMECs, leading to disruption of monolayer barrier integrity. A SILAC-based proteomic screen revealed that BifA binds moesin. BifA’s Fic domain was required for its binding to this regulator of host cell cytoskeletal processes. BifA treatment of hBMECs led to moesin phosphorylation and downstream RhoA activation. Inhibition of moesin activation or moesin depletion in hBMEC monolayers abrogated BifA-mediated increases in barrier permeability and SEZ’s capacity to translocate across monolayers. Thus, BifA activation of moesin appears to constitute a key mechanism by which SEZ disrupts endothelial monolayer integrity to penetrate the BBB.