Programa em Ciências Morfológicas, Programa de Diferenciação Celular, Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil ; Center for Translational Neuromedicine, University of Rochester Medical School Rochester, NY, USA.
Laboratório de Morfogênese Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil.
Front Cell Neurosci. 2015 Feb 17;9:37. doi: 10.3389/fncel.2015.00037. eCollection 2015.
The full spectrum of cellular interactions within CNS neurogenic niches is still poorly understood. Only recently has the monocyte counterpart of the nervous system, the microglial cells, been described as an integral cellular component of neurogenic niches. The present study sought to characterize the microglia population in the early postnatal subventricular zone (SVZ), the major site of postnatal neurogenesis, as well as in its anterior extension, the rostral migratory stream (RMS), a pathway for neuroblasts during their transit toward the olfactory bulb (OB) layers. Here we show that microglia within the SVZ/RMS pathway are not revealed by phenotypic markers that characterize microglia in other regions. Analysis of the transgenic mice strain that has one locus of the constitutively expressed fractalkine CX3CR1 receptor replaced by the gene encoding the enhanced green fluorescent protein (EGFP) circumvented the antigenic plasticity of the microglia, thus allowing us to depict microglia within the SVZ/RMS pathway during early development. Notably, microglia within the early SVZ/RMS are not proliferative and display a protracted development, retaining a more immature morphology than their counterparts outside germinal layers. Furthermore, microglia contact and phagocyte radial glia cells (RG) processes, thereby playing a role on the astroglial transformation that putative stem cells within the SVZ niche undergo during the first postnatal days.
中枢神经系统神经发生龛内细胞相互作用的全貌仍知之甚少。直到最近，神经系统的单核细胞对应物，小胶质细胞，才被描述为神经发生龛的一个组成细胞成分。本研究旨在描述早期室下区（SVZ）中的小胶质细胞群体，SVZ 是产后神经发生的主要部位，以及其前部延伸部，即前迁移流（RMS），这是神经母细胞在向嗅球（OB）层迁移过程中的途径。在这里，我们表明，SVZ/RMS 途径中的小胶质细胞不能通过表征其他区域中小胶质细胞的表型标志物来揭示。通过分析一种转基因小鼠品系，该品系中一个组成型表达的 fractalkine CX3CR1 受体的基因座被编码增强型绿色荧光蛋白（EGFP）的基因取代，避免了小胶质细胞的抗原可塑性，从而使我们能够在早期发育过程中描绘 SVZ/RMS 途径中的小胶质细胞。值得注意的是，早期 SVZ/RMS 中的小胶质细胞没有增殖能力，并且发育时间较长，与生发层外的小胶质细胞相比，它们保持着更不成熟的形态。此外，小胶质细胞与放射状胶质细胞（RG）过程接触并吞噬它们，从而在 SVZ 龛内潜在干细胞在出生后第一天经历的星形胶质细胞转化中发挥作用。
