title: A Distinct Population of Microglia Supports Adult Neurogenesis in the Subventricular Zone.
abstract: Microglia are involved in synaptic pruning both in development and in the mature CNS. In this study, we investigated whether microglia might further contribute to circuit plasticity by modulating neuronal recruitment from the neurogenic subventricular zone (SVZ) of the adult mouse striatum. We found that microglia residing in the SVZ and adjacent rostral migratory stream (RMS) comprise a morphologically and antigenically distinct phenotype of immune effectors. Whereas exhibiting characteristics of alternatively activated microglia, the SVZ/RMS microglia were clearly distinguished by their low expression of purinoceptors and lack of ATP-elicitable chemotaxis. Furthermore, the in vivo depletion of these microglia hampered the survival and migration of newly generated neuroblasts through the RMS to the olfactory bulb. SVZ and RMS microglia thus appear to comprise a functionally distinct class that is selectively adapted to the support and direction of neuronal integration into the olfactory circuitry. Therefore, this unique microglial subpopulation may serve as a novel target with which to modulate cellular addition from endogenous neural stem and progenitor cells of the adult brain.
  
  
  CONCLUSIONS
  Microglial cells are a specialized population of macrophages in the CNS, playing key roles as immune mediators. As integral components in the CNS, the microglia stand out for using the same mechanisms, phagocytosis and cytochemokine release, to promote homeostasis, synaptic pruning, and neural circuitry sculpture. Here, we addressed microglial functions in the subventricular zone (SVZ), the major postnatal neurogenic niche. Our results depict microglia as a conspicuous component of SVZ and its anterior extension, the rostral migratory stream, a pathway used by neuroblasts during their transit toward olfactory bulb layers. In addition to other unique populations residing in the SVZ niche, microglia display distinct morphofunctional properties that boost neuronal progenitor survival and migration in the mammalian brain.
authors: Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902 Brazil, Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, New York 14642, and.
authors: Anna L
authors: AL
authors: Ribeiro Xavier
authors: Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, New York 14642, and.
authors: Benjamin T
authors: BT
authors: Kress
authors: Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, New York 14642, and Center for Basic and Translational Neuroscience, University of Copenhagen, 2200N Copenhagen, Denmark.
authors: Steven A
authors: SA
authors: Goldman
authors: Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902 Brazil.
authors: João R
authors: JR
authors: Lacerda de Menezes
authors: Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, New York 14642, and Center for Basic and Translational Neuroscience, University of Copenhagen, 2200N Copenhagen, Denmark nedergaard@urmc.rochester.edu.
authors: Maiken
authors: http://orcid.org/0000-0001-6502-6031
authors: M
authors: Nedergaard
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D020547:Lateral Ventricles / Q000166:cytology* / Q000502:physiology*; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017628:Microglia / Q000502:physiology*; D058953:Neural Stem Cells / Q000502:physiology; D055495:Neurogenesis / Q000502:physiology*
keywords: microglia; neuroblasts; neurogenesis; purinergic signaling; subventricular zone