Unique role for dentate gyrus microglia in neuroblast survival and in VEGF ‐induced activation

Main Points Dentate gyrus microglia are a unique subpopulation which support neuroblasts survival. Dentate gyrus microglia are characterized by a unique set of genes and by being selectively reactive in response to the angiogenic and neurogenic factor VEGF. AbstractNeurogenic roles of microglia (MG) are thought to include an active role in adult hippocampal neurogenesis in addition to their established roles in pruning surplus dendrites and clearing dead neuroblasts. However, identification of such a role and its delineation in the neurogenic cascade is yet to be established. Using diphtheria toxin ‐aided MG ablation, we show that MG reduction in the DG—the site where neuronal stem cells (NSCs) reside—is sufficient to impede overall hippocampal neurogenesis due to reduced survival of newly formed neuroblasts. To examine whether MG residing in the hippocampal neurogenic zone are inherentl y different from MG residing elsewhere in the hippocampus, we compared growth factor responsiveness of DG MG with that of CA1 MG. Strikingly, transgenic induction of the potent neurogenic factor VEGF elicited robust on‐site MG expansion and activation exclusively in the DG and despite eliciting a comparable angiogenic response in the CA1 and elsewhere. Temporally, DG‐specific MG expansion preceded both angiogenic and neurogenic responses. Remarkably, even partial MG reduction during the process of VEGF‐induced neurogenesis led to reducing the number of newly formed neuroblasts to...
Source: Glia - Category: Neurology Authors: Tags: RESEARCH ARTICLE Source Type: research