Immune cells protect the spinal cord from age-related damage

The scientists studied myelin— the protective sheath of nerve fibers that provides fast and accurate signal transmission. Experiments on mice of different ages have shown that in one of the areas of the spinal cord, the dorsal pillars, myelin gradually accumulates damage as it ages.

The researchers paid special attention to microglia, the immune cells of the brain and spinal cord that are responsible for maintaining the health of the nervous tissue. It is known that microglia can both protect myelin and destroy it when over-activated.

In the course of the work, it turned out that microglia in the aging spinal cord activate the signaling molecule TGF-β. It acts as a brake, preventing immune cells from becoming aggressive and damaging nerve fibers.

To test the importance of this mechanism, the researchers artificially turned off the production of TGF-β in elderly mice. As a result, microglia began to attack myelin, which led to its destruction and the appearance of pronounced movement disorders in animals.

According to the authors of the work, damage in the same area of the spinal cord has previously been detected in people with a number of neurological diseases. The data helps to understand why this particular area is vulnerable and what role the failure of protective immune mechanisms plays in this.

Understanding how microglia inhibit age-related damage may open up new approaches to the prevention and treatment of diseases of the nervous system in the future.