成体神経幹細胞の形成・維持メカニズム

Establishment and Maintenance of Adult Neural Stem Cells

哺乳類の脳では成体においても神経幹細胞が存在し，生涯にわたり神経細胞を新生し続けている。成体における神経新生の異常は，神経変性疾患や精神疾患に関与し得る。生涯という長期間，神経幹細胞が維持されるメカニズムは何か。また，成体神経幹細胞は発生の過程でいつ，どのように産み出されるのか。本総説では成体神経幹細胞の長期維持機構と発生起源について詳説しつつ，成体神経幹細胞研究の現状と今後の展望を概説する。

Abstract

Neural stem cells (NSCs) in the adult mammalian brain produce new neurons throughout life. Defects in adult neurogenesis can influence neurodegenerative and psychiatric disorders. Hence, understanding long-term maintenance of adult NSCs is crucial. Cell-intrinsic and -extrinsic factors contribute to long-term maintenance of adult NSCs, and we have previously reported that NSCs produce their own niches that send a feedback signal for their own maintenance. In addition, we have identified a slowly dividing subpopulation of embryonic neural progenitor cells that is set aside during development, and later becomes a substantial fraction of NSCs in the adult subventricular zone. Here, we review the mechanisms of long-term maintenance and embryonic origin of adult NSCs. We also discuss current topics on adult NSCs and future perspectives in this field of study.