Graduate Program in Neurosciences, University of California, San Diego, CA 92093.
The Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037.
eNeuro. 2017 Jul 31;4(4). doi: 10.1523/ENEURO.0030-17.2017. eCollection 2017 Jul-Aug.
The neurovascular niche is a specialized microenvironment formed by the interactions between neural progenitor cells (NPCs) and the vasculature. While it is thought to regulate adult neurogenesis by signaling through vascular-derived soluble cues or contacted-mediated cues, less is known about the neurovascular niche during development. In tadpole brain, NPCs line the ventricle and extend radial processes tipped with endfeet to the vascularized pial surface. Using labeling and time-lapse imaging in tadpoles, we find that intracardial injection of fluorescent tracers rapidly labels Sox2/3-expressing NPCs and that vascular-circulating molecules are endocytosed by NPC endfeet. Confocal imaging indicates that about half of the endfeet appear to appose the vasculature, and time-lapse analysis of NPC proliferation and endfeet-vascular interactions suggest that proliferative activity does not correlate with stable vascular apposition. Together, these findings characterize the neurovascular niche in the developing brain and suggest that, while signaling to NPCs may occur through vascular-derived soluble cues, stable contact between NPC endfeet and the vasculature is not required for developmental neurogenesis.
神经血管壁龛是由神经祖细胞（NPCs）和血管之间的相互作用形成的一种特殊的微环境。虽然人们认为它通过血管衍生的可溶性信号或接触介导的信号来调节成年神经发生，但在发育过程中，神经血管壁龛的了解较少。在蝌蚪大脑中，NPC 排列在脑室中，并延伸出带有终足的放射状突起，伸向血管化的软脑膜表面。我们通过在蝌蚪中进行荧光标记和延时成像发现，心内注射荧光示踪剂可快速标记 Sox2/3 表达的 NPC，并且血管循环分子被 NPC 终足内吞。共聚焦成像表明，大约一半的终足似乎与血管相对，对 NPC 增殖和终足-血管相互作用的延时分析表明，增殖活性与稳定的血管对位不相关。这些发现共同描述了发育中大脑中的神经血管壁龛，并表明虽然 NPC 可能通过血管衍生的可溶性信号进行信号传递，但 NPC 终足与血管之间的稳定接触对于发育神经发生并非必需。
