NRSC 4132 Blog

I have a very good friend who has a terrible infatuation with glia. Unfortunately in the circles he runs in there are few people with whom he may share his strange fascination without facing merciless ridicule. It seems that in neuroscience you are either in the camp that secretly adores the astrocytes or the one that likes to compare the poor glial cells to the kids who ate their paste in kindergarten. Glia are referred to as housekeeping cells and I?ve heard them called the ?brain?s janitorial staff?, so I sympathized with the lowly glia- dutifully picking up after the all important neurons who were concerned with much more important things- but little did I know these humble glial cells are actually running the show from the start.
In a recent article in Nature Neuroscience researchers found that glia secrete a TGF-b ligand called myoglianin (myo) that actually informs developmental remodeling of neurons. It is well known that as an organism matures its neural circuits are altered and refined, but this study sheds light on the process that triggers this developmental frenzy of cerebral landscaping. In insects such as Drosphila, larval neural circuits are transformed during metamorphosis into adult ones. Neurites are pruned and then extended to form ?adult-specific neural circuits?. This process is highly dependent on TGF-b signaling as it upregulates the expression of EcR-B1 in the late larval stage. Also at this stage myo is secreted in a flood by larval glial cells. When the expression of myoglianin was silenced, the pruning and re-extension of larval neurites did not occur. The very form a brain takes is influenced from the beginning by glia. Without glia and myo these drosophila retain their larval neural network because superfluous connections aren't pruned and important "adult" networks aren't reinforced and strengthened.
It?s easy to make fun of glia, but they aren?t useless or dumb. They may be housekeepers, but they are the housekeepers from Gosford Park. Glia only let neurons THINK they are in charge. The truth is that glia deserve the same respect as neurons, and this is blatantly obvious when you look at diseases of the brain that origninate in or affect glial cells such as Parkinson?s and Alzheimer?s diseases. The roles that glia play are vital to the health of our brains and when they cease to function normally so do we. I think this study may be important in illuminating how glia may influence synaptic plasticity and long term potentiation in neural circuits. This is an exciting time for fans of glia.
Full article can be found here.
http;//www.nature.com+nn.2833.html