Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 875 Ellicott Street, 8-022A Buffalo, New York, NY, 14203, United States.
Mol Immunol. 2018 Oct;102:26-31. doi: 10.1016/j.molimm.2018.06.267. Epub 2018 Jul 12.
The brain is an immune privileged organ, uniquely placed in the body. Two systems involved in maintaining brain homeostasis and in protecting the brain are the blood-brain barrier (BBB) and the complement system. The BBB is present in the vasculature of the brain and is the dynamic interface between brain and body that regulates what enters and leaves the brain, thereby maintaining the brain microenvironment optimal for brain function. The complement system is ubiquitous, being present systemically and in the brain, both membrane bound and in circulation. It is an important arm of the body's defense that helps maintain homeostasis by eliminating debris and damaged cells, participating in destroying pathogens, promoting inflammation and conveying 'danger signals'. Recent studies reveal that the complement system plays an important role in normal brain development. However, when the complement system is overwhelmed, complement activation could contribute to loss of BBB integrity resulting in brain pathology. Studies support an association between complement proteins and BBB dysfunction, with the mechanisms being slowly unraveled. This review will provide an overview of both these systems, how they intersect and interact with each other.
大脑是一个具有免疫特权的器官，在体内具有独特的位置。参与维持大脑内环境稳定和保护大脑的两个系统是血脑屏障 (BBB) 和补体系统。BBB 存在于大脑的血管中，是大脑和身体之间的动态界面，调节着进入和离开大脑的物质，从而维持有利于大脑功能的大脑微环境。补体系统无处不在，存在于全身和大脑中，既有膜结合形式，也有循环形式。它是身体防御的重要组成部分，通过清除碎片和受损细胞、参与破坏病原体、促进炎症和传递“危险信号”来帮助维持内环境稳定。最近的研究表明，补体系统在正常大脑发育中起着重要作用。然而，当补体系统不堪重负时，补体的激活可能会导致 BBB 完整性丧失，从而导致脑部病变。研究支持补体蛋白与 BBB 功能障碍之间存在关联，其机制正在逐渐被揭示。这篇综述将概述这两个系统，以及它们是如何相互交叉和相互作用的。
