title: Ontogeny and functions of central nervous system macrophages.
abstract: Microglia, the only nonneuroepithelial cells found in the parenchyma of the CNS, originate during embryogenesis from the yolk sac and enter the CNS quite early (embryonic day 9.5-10 in mice). Thereafter, microglia are maintained independently of any input from the blood and, in particular, do not require hematopoietic stem cells as a source of replacement for senescent cells. Monocytes are hematopoietic cells, derived from bone marrow. The ontogeny of microglia and monocytes is important for understanding CNS pathologies. Microglial functions are distinct from those of blood-derived monocytes, which invade the CNS only under pathological conditions. Recent data reveal that microglia play an important role in managing neuronal cell death, neurogenesis, and synaptic interactions. In this article, we discuss the physiology of microglia and the functions of monocytes in CNS pathology. We address the roles of microglia and monocytes in neurodegenerative diseases as an example of CNS pathology.
authors.affiliation: Neuroinflammation Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; and.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Katsumoto
authors.affiliation: Neuroinflammation Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; and.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Lu
authors.affiliation: Neuroinflammation Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; and.
authors.forename: Aline S
authors.initials: AS
authors.lastname: Miranda
authors.affiliation: Neuroinflammation Research Center, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; and Mellen Center for Multiple Sclerosis Treatment and Research, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195 ransohr@ccf.org.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Ransohoff
mesh_terms: D000818:Animals; D017209:Apoptosis; D002450:Cell Communication / Q000276:immunology; D002454:Cell Differentiation; D019070:Cell Lineage / Q000276:immunology; D002490:Central Nervous System / Q000166:cytology / Q000276:immunology / Q000473:pathology*; D006801:Humans; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000276:immunology / Q000473:pathology*; D019636:Neurodegenerative Diseases / Q000276:immunology / Q000473:pathology*; D055495:Neurogenesis