Kim Brandon J, Bee Olivia B, McDonagh Maura A, Stebbins Matthew J, Palecek Sean P, Doran Kelly S, Shusta Eric V
Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin, USA.
Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA.
mSphere. 2017 Nov 1;2(6). doi: 10.1128/mSphere.00398-17. eCollection 2017 Nov-Dec.
Bacterial meningitis is a serious infection of the central nervous system (CNS) that occurs after bacteria interact with and penetrate the blood-brain barrier (BBB). The BBB is comprised of highly specialized brain microvascular endothelial cells (BMECs) that function to separate the circulation from the CNS and act as a formidable barrier for toxins and pathogens. Certain bacteria, such as (group B [GBS]), possess the ability to interact with and penetrate the BBB to cause meningitis. Modeling bacterial interaction with the BBB has been limited to primary and immortalized BMEC culture. While useful, these cells often do not retain BBB-like properties, and human primary cells have limited availability. Recently, a human induced pluripotent stem cell (iPSC)-derived BMEC model has been established that is readily renewable and retains key BBB phenotypes. Here, we sought to evaluate whether the iPSC-derived BMECs were appropriate for modeling bacterial interaction with the BBB. Using GBS as a model meningeal pathogen, we demonstrate that wild-type GBS adhered to, invaded, and activated the iPSC-derived BMECs, while GBS mutants known to have diminished BBB interaction were attenuated in the iPSC-derived model. Furthermore, bacterial infection resulted in the disruption of tight junction components ZO-1, occludin, and claudin-5. Thus, we show for the first time that the iPSC-derived BBB model can be utilized to study BBB interaction with a bacterial CNS pathogen. Here for the first time, human iPSC-derived BMECs were used to model bacterial interaction with the BBB. Unlike models previously used to study these interactions, iPSC-derived BMECs possess robust BBB properties, such as the expression of complex tight junctions that are key components for the investigation of bacterial effects on the BBB. Here, we demonstrated that GBS interacts with the iPSC-derived BMECs and specifically disrupts these tight junctions. Thus, using this BBB model may allow researchers to uncover novel mechanisms of BBB disruption during meningitis that are inaccessible to immortalized or primary cell models that lack substantial tight junctions.
细菌性脑膜炎是一种中枢神经系统（CNS）的严重感染，它发生在细菌与血脑屏障（BBB）相互作用并穿透血脑屏障之后。血脑屏障由高度特化的脑微血管内皮细胞（BMECs）组成，其功能是将循环系统与中枢神经系统分隔开，并作为毒素和病原体的强大屏障。某些细菌，如B组链球菌（GBS），具有与血脑屏障相互作用并穿透血脑屏障导致脑膜炎的能力。模拟细菌与血脑屏障的相互作用一直局限于原代和永生化的BMEC培养。虽然这些细胞有用，但它们通常不保留类似血脑屏障的特性，而且人类原代细胞的可用性有限。最近，已经建立了一种人诱导多能干细胞（iPSC）衍生的BMEC模型，该模型易于再生并保留关键的血脑屏障表型。在这里，我们试图评估iPSC衍生的BMECs是否适合模拟细菌与血脑屏障的相互作用。使用GBS作为模型脑膜病原体，我们证明野生型GBS粘附、侵入并激活了iPSC衍生的BMECs，而已知与血脑屏障相互作用减弱的GBS突变体在iPSC衍生模型中则减弱。此外，细菌感染导致紧密连接成分ZO-1、闭合蛋白和claudin-5的破坏。因此，我们首次表明iPSC衍生的血脑屏障模型可用于研究血脑屏障与细菌性中枢神经系统病原体的相互作用。在这里首次使用人iPSC衍生的BMECs来模拟细菌与血脑屏障的相互作用。与以前用于研究这些相互作用的模型不同，iPSC衍生的BMECs具有强大的血脑屏障特性，例如复杂紧密连接的表达，这些紧密连接是研究细菌对血脑屏障影响的关键成分。在这里，我们证明GBS与iPSC衍生的BMECs相互作用并特异性破坏这些紧密连接。因此，使用这个血脑屏障模型可能使研究人员发现脑膜炎期间血脑屏障破坏的新机制，而这些机制是缺乏大量紧密连接的永生化或原代细胞模型无法触及的。
