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microglia (Hortega cell)

Brain mononuclear phagocytes with functions similar to tissue macrophages: Function: 1) phagocytosis 2) antigen presentation 3) production of: (see proteins expressed by microglia) a) cytokines b) chemokines c) eicosanoids d) complement compenents e) matrix metalloproteinases f) reactive oxygen species Microglia populate the brain early in fetal development & persist as long-lived cells. They mature in the brain parenchyma & display a quiescent phenotype. Pathology: - IFN-gamma activates microglia - A4 amyloid peptide (A-beta) activates microglia; A-beta stimulation of microglia are mediated by: a) AGE-receptor (RAGE) b) scavenger receptors c) other factors Comparative biology: - West Nile virus infection of neurons triggers activation of the complement cascade within the hippocampus of mice [2] - microglia then trim presynaptic terminals in response to complement activation (neurons remain viable) - CX3CR1-positive microglia in mice associate with brain capillaries - purines released through PANX1 channels may play important roles in activating microglial P2RY12 receptors to regulate neurovascular structure & function [3]

Related

A4 amyloid peptide; beta-peptide advanced glycosylation end product [AGE] receptor (AGER, RAGE) proteins expressed by microglia scavenger receptor

General

neuroglia phagocyte

Properties

WITHIN: central nervous system

References

  1. Benveniste et al, Neurochemistry International 39:381, 2001
  2. Vasek MJ, Garber C, Dorsey D et al A complement-microglial axis drives synapse loss during virus- induced memory impairment. Nature. 2016 Jun 22;534(7608):538-43. PMID: 27337340
  3. Bisht K, Okojie KA, Sharma K et al Capillary-associated microglia regulate vascular structure and function through PANX1-P2RY12 coupling in mice. Nature Communications, 2021; Sep 6;12(1):5289 PMID: 34489419 PMCID: PMC8421455 Free PMC article