As you read this sentence, an army of cells patrols your brain. These soldiers slither along neurons, using their lumbering appendages to scan for threats. If one detects a pathogen or injury, it springs into action. Swelling and collapsing in a voracious attack, it releases chemicals that signal its comrades to join the fight.
Known as microglia, these specialized immune cells are our brain's chief defenders. They protect us from invaders, clear out debris, and maintain connections between neurons to ensure the brain stays in tip-top shape.
Despite their vigilance, however, microglia can sometimes turn on their own, and mounting evidence suggests they may be the engineers behind some of the most intractable brain conditions, such as Alzheimer’s and depression. If so, targeting our wayward defenders—or even replacing them with rejuvenated troops—could lead to exciting new treatments.
Microglia was discovered in 1919 neurobiologist Pio del Rio OrtegaWhile experimenting with new ways of staining brain tissue, he came across these new cells and named them after the ancient Greek words meaning “small” and “glue.”
That turned out to be an inadequate description. Beyond their patchy appearance, microglia have few glue-like qualities. Instead, they are among the most dynamic cells in the body, roaming the brain in spindly, tentacle-like projections that extend and retract in response to changes in the environment.
How Microglia Function
Microglia are a form of macrophage, a type of immune cell whose role is…