Molecules, Cells, and Organisms Training Program, Harvard University, Cambridge, United States.
Center for Brain Science, Harvard University, Cambridge, United States.
Elife. 2020 Mar 9;9:e50531. doi: 10.7554/eLife.50531.
Microglia play key roles in regulating synapse development and refinement in the developing brain, but it is unknown whether they are similarly involved during adult neurogenesis. By transiently depleting microglia from the healthy adult mouse brain, we show that microglia are necessary for the normal functional development of adult-born granule cells (abGCs) in the olfactory bulb. Microglial depletion reduces the odor responses of developing, but not preexisting GCs in vivo in both awake and anesthetized mice. Microglia preferentially target their motile processes to interact with mushroom spines on abGCs, and when microglia are absent, abGCs develop smaller spines and receive weaker excitatory synaptic inputs. These results suggest that microglia promote the development of excitatory synapses onto developing abGCs, which may impact the function of these cells in the olfactory circuit.
小胶质细胞在调节发育中大脑的突触发育和精细化方面发挥着关键作用，但尚不清楚它们在成年神经发生过程中是否同样参与。通过短暂耗尽健康成年小鼠大脑中的小胶质细胞，我们表明小胶质细胞对于嗅球中成年新生颗粒细胞（abGCs）的正常功能发育是必需的。小胶质细胞耗竭减少了在清醒和麻醉小鼠体内发育中的但不是预先存在的 GC 的气味反应。小胶质细胞优先将其运动过程靶向到与 abGC 上的蘑菇形刺突相互作用，并且当小胶质细胞不存在时，abGC 发育出更小的刺突并接收较弱的兴奋性突触输入。这些结果表明，小胶质细胞促进了兴奋性突触的发育，从而作用于发育中的 abGCs，这可能会影响这些细胞在嗅觉回路中的功能。
