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Journal of Immunology Research
Volume 2017 (2017), Article ID 5150678, 12 pages
https://doi.org/10.1155/2017/5150678
Review Article

The Role of Microglia and Macrophages in CNS Homeostasis, Autoimmunity, and Cancer

1Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL 35233, USA
2Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
3Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China

Correspondence should be addressed to Jianmei W. Leavenworth

Received 29 July 2017; Revised 20 October 2017; Accepted 27 November 2017; Published 19 December 2017

Academic Editor: Hao Liu

Copyright © 2017 Jie Yin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Macrophages are major cell types of the immune system, and they comprise both tissue-resident populations and circulating monocyte-derived subsets. Here, we discuss microglia, the resident macrophage within the central nervous system (CNS), and CNS-infiltrating macrophages. Under steady state, microglia play important roles in the regulation of CNS homeostasis through the removal of damaged or unnecessary neurons and synapses. In the face of inflammatory or pathological insults, microglia and CNS-infiltrating macrophages not only constitute the first line of defense against pathogens by regulating components of innate immunity, but they also regulate the adaptive arms of immune responses. Dysregulation of these responses contributes to many CNS disorders. In this overview, we summarize the current knowledge regarding the highly diverse and complex function of microglia and macrophages during CNS autoimmunity—multiple sclerosis and cancer—malignant glioma. We emphasize how the crosstalk between natural killer (NK) cells or glioma cells or glioma stem cells and CNS macrophages impacts on the pathological processes. Given the essential role of CNS microglia and macrophages in the regulation of all types of CNS disorders, agents targeting these subsets are currently applied in preclinical and clinical trials. We believe that a better understanding of the biology of these macrophage subsets offers new exciting paths for therapeutic intervention.