ミクログリアによる血液脳関門機能の制御

Microglial Regulation of Blood Brain Barrier, the Neuro-Immunological Interface

中枢神経系の免疫環境は，血液脳関門（BBB）により完全に体循環系と隔たれているとされていた。しかし近年，全身の免疫状態が中枢神経系にもたらす影響について知見が深まり，さらに新型感染症の拡大を皮切りに，BBBを介した体循環系-中枢神経系相互作用に注目が集まっている。新たな潮流への理解を深めるため，本論では中枢神経系の免疫細胞によるBBBの制御や体循環系免疫との相互作用について概説する。

Abstract

The central nervous system (CNS) is an immune-privileged area. The blood-brain barrier (BBB) is thought to separate the CNS from any systemic inflammatory states to maintain homeostasis within this specialized, vulnerable organ. However, accumulating studies have challenged this concept by demonstrating systemic inflammatory effects on brain. Moreover, the coronavirus disease pandemic caused by severe acute respiratory syndrome coronavirus 2 in 2019 has rapidly evoked attention toward the BBB as the systemic-CNS immunological interface. In this review, we focus on microglia, the sole immune cells in the CNS, and briefly introduce our new findings regarding microglial BBB regulation in systemic inflammation. With a close eye on associated literature, we carefully rethink the traditional immune system in the CNS and suggest a new possible mechanism of systemic-CNS immune cell interaction, while an understanding of the BBB develops.