Espinal Eric R, Matthews Teralan, Holder Brianna M, Bee Olivia B, Humber Gabrielle M, Brook Caroline E, Divyapicigil Mustafa, Sharp Jerod, Kim Brandon J
Department of Biological Sciences, University of Alabama, 300 Hackberry Lane, Tuscaloosa, AL 35405, USA.
Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI 53706, USA.
Pathogens. 2022 Apr 15;11(4):474. doi: 10.3390/pathogens11040474.
Bacterial meningitis is defined as serious inflammation of the central nervous system (CNS) in which bacteria infect the blood-brain barrier (BBB), a network of highly specialized brain endothelial cells (BECs). Dysfunction of the BBB is a hallmark of bacterial meningitis. Group B (GBS) is one of the leading organisms that cause bacterial meningitis, especially in neonates. Macropinocytosis is an actin-dependent form of endocytosis that is also tightly regulated at the BBB. Previous studies have shown that inhibition of actin-dependent processes decreases bacterial invasion, suggesting that pathogens can utilize macropinocytotic pathways for invasion. The purpose of this project is to study the factors that lead to dysfunction of the BBB. We demonstrate that infection with GBS increases rates of endocytosis in BECs. We identified a potential pathway, PLC-PKC-Nox2, in BECs that contributes to macropinocytosis regulation. Here we demonstrate that downstream inhibition of PLC, PKC, or Nox2 significantly blocks GBS invasion of BECs. Additionally, we show that pharmacological activation of PKC can turn on macropinocytosis and increase bacterial invasion of nonpathogenic yet genetically similar . Our results suggest that GBS activates BEC signaling pathways that increase rates of macropinocytosis and subsequently the invasion of GBS.
细菌性脑膜炎被定义为中枢神经系统（CNS）的严重炎症，其中细菌感染血脑屏障（BBB），这是一个由高度特化的脑内皮细胞（BECs）组成的网络。血脑屏障功能障碍是细菌性脑膜炎的一个标志。B族链球菌（GBS）是导致细菌性脑膜炎的主要病原体之一，尤其是在新生儿中。巨胞饮作用是一种肌动蛋白依赖性的内吞形式，在血脑屏障处也受到严格调控。先前的研究表明，抑制肌动蛋白依赖性过程会减少细菌入侵，这表明病原体可以利用巨胞饮途径进行入侵。本项目的目的是研究导致血脑屏障功能障碍的因素。我们证明，GBS感染会增加BECs的内吞率。我们在BECs中确定了一条潜在的途径，即PLC-PKC-Nox2，它有助于巨胞饮作用的调节。在这里，我们证明对PLC、PKC或Nox2的下游抑制可显著阻断GBS对BECs的入侵。此外，我们表明PKC的药理学激活可开启巨胞饮作用，并增加非致病性但基因相似的细菌的入侵。我们的结果表明，GBS激活BEC信号通路，增加巨胞饮率，进而增加GBS的入侵。
