BLOG: The Backbone of Neurons
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As they age neurons lose their ability to regenerate. However, they do not lose it entirely. Some scientists believe that this loss is due to an alteration of their skeleton. The so-called cytoskeleton is therefore an interesting target for restoring the growth capacity.
Let`s start with the basics
Neurons consist of a cell body and a very long structure called the axon that connects them to other distant cells. The injury cuts these axons and the stump that is still connected to the cell body will develop a structure called the growth cone. As its name suggests, the growth cone allows the axon to grow again and regenerate. The cytoskeleton plays an important role in this process and enables the cells to build up these growth cones.
What happens after spinal cord injury?
In another context, there is one moment in our lives when growth cones succeed at growing and reach their target: during embryonal development. They lead to the elongation of the axon and the formation of long nerve cables. Unfortunately, these attempts are unsuccessful in adults after spinal cord injury. The growth cone finally transforms into a retraction bulb. As the name retraction bulb indicates, they are oval structures that fail to grow. Unlike growth cones, they appear disorganized but surprisingly still display a certain dynamism: These atrophic ends move back and forth.
Cytoskeleton supports growth cone formation
A stabilized cytoskeleton is a condition for building growth cones. They are compounds that can stabilize the backbone of the growing axon. In fact, in vitro treatment with paclitaxel (a chemotherapy against cancer), or epothilone B (another class of potential cancer drugs) improve growth cone formation in adult spinal cord neurons. This category of drugs offers a very interesting target to promote regeneration.
And this is true for two additional reasons. First, they seem to help transport the signal that neurons are damaged and that they need to regrow. Second, recent experiments show that they diminish the formation of a scar and limit the number of inhibitory molecules.
What does that mean?
Although further research is needed to understand the molecular players that lead to positive cytoskeletal re-arrangements, manipulation of the cytoskeleton offers a very good target to promote regeneration after spinal cord injury.
Wings for Life has been supporting research in such a project for several years.