Microglia are innate immune cells of the brain, responsible for the immediate defense against pathogens. In the past, microglia were thought to be sessile cells serving as glue for neurons in the brain. Their name microglia originated from the two words “micro” and “glue”. Almost 20 years ago, researchers found that microglia are highly motile cells constantly scanning the brain parenchyma with their fine processes. A novel microscopy technique called “two-photon imaging” enabled to record movies of cells in the brain of living animals and led to this discovery. Although microglia seemed to have a primary role in defense and ingestion of leftover cell material, novel results pointed at a role at synapse stability and regulation of neuronal activity. We think that microglia are not just garbage collectors, they are also sensitive cells that are creators of new connections between neurons – the so-called synapses. The project MicroSynCom tries to reveal the mechanisms how microglia mediate the formation of new synapses. This would assign a novel, so far unknown, function to microglia. If we understand the mechanisms how microglia mediate the formation of new synapses, we may use this knowledge to initiate this function via drugs. There are several diseases, especially neurodegenerative and neurologic diseases that are characterized by a dramatic synapse loss. If we would find drugs that are able to trigger the formation of new synapses via microglia, these diseases may be ultimately treatable. Therefore, we aim to establish microglia as mediators of new synapse formation.
