Stories about: microglia2018

Microglia in the brain: Which are good and which are bad?

Timothy Hammond studying brain microglia in the Stevens Lab at Boston Children's Hospital
If we see microglia in brain disease, are they part of the problem, or part of the solution? asks Timothy Hammond. (PHOTOS: MICHAEL GODERRE / BOSTON CHILDREN’S HOSPITAL)

Microglia are known to be important to brain function. The immune cells have been found to protect the brain from injury and infection and are critical during brain development, helping circuits wire properly. They also seem to play a role in disease — showing up, for example, around brain plaques in people with Alzheimer’s.

It turns out microglia aren’t monolithic. They come in different flavors, and unlike the brain’s neurons, they’re always changing. Tim Hammond, PhD, a neuroscientist in the Stevens lab at Boston Children’s Hospital, showed this in an ambitious study, perhaps the most comprehensive survey of microglia ever conducted. Published last week in Immunity, the findings open a new chapter in brain exploration.

Read Full Story | Leave a Comment

Synapse ‘protection’ signal found; helps to refine brain circuits

a combination of 'eat me' and 'don't eat me' signals fine-tune synapse pruning
New evidence suggests that a ‘yin/yang’ system fine-tunes brain connections and synapse pruning (IMAGE: NANCY FLIESLER/ADOBE STOCK)

The developing brain is constantly forming new connections, or synapses, between nerve cells. Many connections are eventually lost, while others are strengthened. In 2012, Beth Stevens, PhD and her lab at Boston Children’s Hospital showed that microglia, immune cells that live in the brain, prune back unwanted synapses by engulfing or “eating” them. They also identified a set of “eat me” signals required to promote this process: complement proteins, best known for helping the immune system combat infection.

In new work published today in Neuron, Stevens and colleagues reveal the flip side: a “don’t eat me” signal that prevents microglia from pruning useful connections away.

Read Full Story | Leave a Comment