Department of Psychology, The Hebrew University of Jerusalem, Jerusalem, Israel
Elena Kudryavitskaya
Department of Neurobiology, Institute for Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
Haran Shani-Narkiss
Department of Neurobiology, Institute for Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
Batya Isaacson
Department of Immunology and Cancer Research, The Lautenberg Center for General and Tumor Immunology, The Hebrew University of Jerusalem, Jerusalem, Israel
Neta Rimmerman
Department of Psychology, The Hebrew University of Jerusalem, Jerusalem, Israel
Adi Mizrahi
Department of Neurobiology, Institute for Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
Microglia play important roles in perinatal neuro- and synapto-genesis. To test the role of microglia in these processes during adulthood, we examined the effects of microglia depletion, via treatment of mice with the CSF-1 receptor antagonist PLX5622, and abrogated neuronal-microglial communication in CX3C receptor-1 deficient (Cx3cr1−/−) mice. Microglia depletion significantly lowered spine density in young (developing) but not mature adult-born-granule-cells (abGCs) in the olfactory bulb. Two-photon time-lapse imaging indicated that microglia depletion reduced spine formation and elimination. Functionally, odor-evoked responses of mitral cells, which are normally inhibited by abGCs, were increased in microglia-depleted mice. In Cx3cr1−/− mice, abGCs exhibited reduced spine density, dynamics and size, concomitantly with reduced contacts between Cx3cr1-deficient microglia and abGCs' dendritic shafts, along with increased proportion of microglia-contacted spines. Thus, during adult neurogenesis, microglia regulate the elimination (pruning), formation, and maintenance of synapses on newborn neurons, contributing to the functional integrity of the olfactory bulb circuitry.
