Molecules, Cells, and Organisms Training Program, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States; Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States; FM Kirby Neurobiology Center, Boston Children’s Hospital, Boston, United States
Julia Lord
Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
Lasse Dissing-Olesen
FM Kirby Neurobiology Center, Boston Children’s Hospital, Boston, United States; Harvard Medical School, Boston, United States
FM Kirby Neurobiology Center, Boston Children’s Hospital, Boston, United States; Harvard Medical School, Boston, United States; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States; Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, United States
Molecules, Cells, and Organisms Training Program, Harvard University, Cambridge, United States; Center for Brain Science, Harvard University, Cambridge, United States; Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
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.
