On the way to spinal cord regeneration
A step has been taken to restore nerves after a spinal fracture
Georgy Golovanov, Hi-tech+
Damaged peripheral nerves can recover after injury, for example, a broken arm. German scientists have studied the nuances of this process and have shown that the same mechanism can be activated in the cells of the central nervous system.
Injury to the peripheral nervous system quickly triggers the activation of the recovery process, which regenerates the damaged nerve. The central nervous system does not have this ability, and therefore spinal fractures often lead to paralysis of body parts controlled by nerves located below the injury site.
The key to the regenerative process of axons – long processes of nerve cells – the so-called myelin-forming cells. Many axons are enclosed in a myelin sheath, which serves as a protective layer, and also provides fast and efficient signal transmission. It plays an important role in the nervous system, but also prevents recovery in case of injury.
Myelin is produced by Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system. This difference is key for nerve regeneration, because Schwann cells and oligodendrocytes react very differently to axon damage.
Schwann cells do everything possible to destroy damaged axon segments as quickly as possible. To do this, they create spheres of actin protein, which exert pressure on isolated areas of axons until they break up into small pieces. After that, they can be absorbed. This destruction of unnecessary cells is an important step in the process of growth of a new nerve.
Oligodendrocytes, on the other hand, do not know how to form actin spheres, since, at least, they cannot trigger the expression of the VEGFR1 receptor.
Scientists managed to induce this process in oligodendrocytes, which led to the development of actin structures and the destruction of isolated axon fragments.
Actin spheres (green) wrapped around a severed axon (red). Image: Adrien Vaquié, from the Johannes Gutenberg University Mainz press release First step to induce self-repair in the central nervous system.
Article by Vaquié et al. Injured Axons Instruct Schwann Cells to Build Constricting Actin Spheres to Accelerate Axonal Disintegration is published in the journal Cell Reports – VM.
Now biologists are working on the second step to the restoration of cells of the central nervous system – the search for the molecular process responsible for the removal of myelin.
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