Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America.
Center for Stem Cells and Regenerative Medicine, University of Notre Dame, Notre Dame, Indiana, United States of America.
PLoS Biol. 2019 Feb 22;17(2):e3000159. doi: 10.1371/journal.pbio.3000159. eCollection 2019 Feb.
Microglia are central nervous system (CNS)-resident cells. Their ability to migrate outside of the CNS, however, is not understood. Using time-lapse imaging in an obstetrical brachial plexus injury (OBPI) model, we show that microglia squeeze through the spinal boundary and emigrate to peripheral spinal roots. Although both macrophages and microglia respond, microglia are the debris-clearing cell. Once outside the CNS, microglia re-enter the spinal cord in an altered state. These peripheral nervous system (PNS)-experienced microglia can travel to distal CNS areas from the injury site, including the brain, with debris. This emigration is balanced by two mechanisms-induced emigration via N-methyl-D-aspartate receptor (NMDA) dependence and restriction via contact-dependent cellular repulsion with macrophages. These discoveries open the possibility that microglia can migrate outside of their textbook-defined regions in disease states.
小胶质细胞是中枢神经系统（CNS）驻留细胞。然而，它们离开 CNS 进行迁移的能力尚未被理解。通过在产科臂丛神经损伤（OBPI）模型中进行延时成像，我们发现小胶质细胞能够挤压穿过脊髓边界并迁移到外周脊神经根。尽管巨噬细胞和小胶质细胞都有反应，但小胶质细胞是清除碎片的细胞。一旦离开 CNS，小胶质细胞就会以一种改变的状态重新进入脊髓。这些外周神经系统（PNS）经历过的小胶质细胞可以携带碎片从损伤部位迁移到 CNS 的远端区域，包括大脑。这种迁移通过两种机制达到平衡：通过 N-甲基-D-天冬氨酸受体（NMDA）依赖性诱导迁移，以及通过与巨噬细胞的接触依赖性细胞排斥来限制迁移。这些发现为小胶质细胞在疾病状态下可以迁移到其教科书定义的区域之外的可能性打开了大门。
