Microglial phenotype: is the commitment reversible?

• Published in: Trends in neurosciences (Regular ed.) 2006-02, Vol.29 (2), p.68-74
• Main Authors: Schwartz, Michal, Butovsky, Oleg, Brück, Wolfgang, Hanisch, Uwe-Karsten
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cells; Fundamental and applied biological sciences. Psychology; Genotype & phenotype; Humans; Immune system; Inflammation - pathology; Isolated neuron and nerve. Neuroglia; Microglia - physiology; Neurosciences; Phenotype; Vertebrates: nervous system and sense organs
• ISSN: 0166-2236; 1878-108X
• DOI: 10.1016/j.tins.2005.12.005

Microglia, the standby cells for immune defense in the CNS, have a reputation for exacerbating the neural damage that occurs in neurodegenerative diseases. However, research over the past few years has established that microglia do not constitute a single, uniform cell population, but rather comprise a family of cells with diverse phenotypes – some that are beneficial and others that the CNS can barely tolerate and that are therefore destructive. This finding raised several questions. What instructs microglia to acquire a particular phenotype, and how do these phenotypes differ? How committed are microglia to a specific phenotype? Can destructive microglia become protective, and can protective microglia retain their beneficial phenotype even when they encounter a destructive environment? Here, we address these questions, and the background of research that elicited them.