Host factors and bacterial meningitis

 描述(申请人提供)：细菌性脑膜炎仍然是导致死亡和发病的重要原因，如发育迟缓、听力损失和认知障碍。大都会亚特兰大发育障碍监测计划确定细菌性脑膜炎是导致发育障碍的主要出生后原因。造成这种死亡率和发病率的一个主要因素是我们对这种疾病的发病机制了解不够全面。大肠埃希菌是引起脑膜炎的最常见的革兰氏阴性杆菌。来自人类病例和实验动物模型的几条证据表明，大肠杆菌进入大脑的过程中伴随着高水平的菌血症，而大脑毛细血管是大肠杆菌进入大脑的门户。由于大肠埃希菌进入脑内是通过脑微血管内皮细胞进入脑内的，因此我们利用人脑微血管内皮细胞(HBMEC)建立了血脑屏障模型，以研究大肠杆菌对血脑屏障的穿透作用。我们的HBMEC单层在胶原包裹的Trswells上培养后，显示出紧密和粘连连接蛋白的空间组织以及极化的单层，这是血脑屏障内皮细胞的独特属性。我们首次证明了导致脑膜炎的大肠杆菌菌株具有入侵HBMEC单层的能力，并且HBMEC的入侵能力与大肠杆菌在体内的脑渗透有关。然而，大肠杆菌穿透血脑屏障的潜在机制仍然不完全清楚。这些发现表明，需要新的方法来研究大肠杆菌对血脑屏障的渗透。我们已经使用大肠杆菌入侵HBMEC单层作为一种生物学相关的新方法来发现影响大肠杆菌穿透血脑屏障的靶点。这一应用是为了利用从我们的化学筛选中确定的新靶点来研究它们如何在体外和体内促进大肠杆菌对血脑屏障的穿透。对这些靶点的表征将展示一种新的策略，该策略由引起脑膜炎的大肠杆菌菌株利用来穿透血脑屏障，这是大肠杆菌脑膜炎发展的关键步骤。

 DESCRIPTION (provided by applicant): Bacterial meningitis continues to be an important cause of mortality and morbidity, such as developmental delay, hearing loss and cognitive impairment. The Metropolitan Atlanta Developmental Disabilities Surveillance Program identified bacterial meningitis as the leading postnatal cause of developmental disabilities. A major contributing factor to such mortality and morbidity is our incomplete knowledge on the pathogenesis of this disease. E. coli is the most common Gram-negative bacillary organism causing meningitis. Several lines of evidence from human cases and experimental animal models of E. coli meningitis indicate that E. coli penetration into the brain follows a high level f bacteremia and cerebral capillaries are the portal of E. coli entry into the brain. Since E. coli entry into the brain occurred in the cerebral microvessels, we developed the blood-brain barrier model with human brain microvascular endothelial cells (HBMEC) to study E. coli penetration of the blood-brain barrier. Our HBMEC monolayer, upon cultivation on collagen-coated Transwells, exhibits spatial organization of tight and adherens junction proteins as well as a polarized monolayer, a unique property of the blood-brain barrier endothelial cells. We have shown for the first time that meningitis-causing E. coli strains exhibit the ability to invade the HBMEC monolayer and that the ability of HBMEC invasion is correlated with E. coli penetration into the brain in vivo. The underlying mechanisms involved in E. coli penetration of the blood-brain barrier, however, remain incompletely understood. These findings indicate that new approaches are needed to investigate E. coli penetration of the blood-brain barrier. We have used E. coli invasion of HBMEC monolayer as a biologically relevant new approach for discovery of targets affecting E. coli penetration of the blood-brain barrier. This application is to take advantage of the new targets identified from our chemical screen for investigating how they contribute to E. coli penetration of the blood-brain barrier in vitro and in vivo. Characterization of such targets will demonstrate a novel strategy exploited by meningitis-causing E. coli strains for penetration of the blood-brain barrier, the essential step in the development of E. coli meningitis.