Research on Schwann cells able to generate protective myelin on the nerves

The researchers found that Schwann cells, a particular type of cell, are able to generate protective sheaths of the myelin sheath for nerves at speeds higher than previously thought.

Dr. Kelly Monk, lead author, professor and co-director of the Vollum Institute of Oregon Health & Science University, said in a statement: "This totally reverses the definition of the Schwann Cell Function Manual." The study titled "Myelinating Schwann cells" multiple axon sheath in the absence of E3 ligase component Fbxw7 ", was published in the latest issue of the journal Nature Communications.

This discovery could be very beneficial for people with neuropathies and nerve damage, says the team. This could also be very beneficial for people with multiple sclerosis (MS). In MS, the myelin sheath surrounding nerves is severely damaged, slowing or stopping nerve signals.

The researchers explain that this discovery may be significant in a disorder of the peripheral nervous system such as Charcot-Marie-Tooth disease, that the myelin is damaged and that the condition is extremely painful. They add that a new gene therapy could be used to repair the damaged myelin sheath and generate a new myelin to cover the nerves. In the United States, one in 2,500 people have developed Charcot Marie Tooth disease and could benefit from this therapy, according to the researchers.

Myelin sheath of the neuron. A Schwann cell envelops and rotates around the axon forming the myelin sheath. This axon is now myelinated. Detailed Anatomy Detail – Illustration Credit: Tefi / Shutterstock

The team explains that there are two types of cells in the body that are responsible for producing myelin to protect the nerves. These are oligodendrocytes present in the brain and spinal cord, as well as Schwann cells present elsewhere. Current knowledge extends to the fact that oligodendocytes are the only cells that generate myelin sheaths to coat axons or elongated nerve cell bodies of the central nervous system and act individually on the nerves. These axons are like wiring and carry electrical signals between two cells. This new study revealed that Schwann cells are just as capable of producing myelin, especially in the peripheral nervous system. The authors explain in their article: "The composition and structure of myelin sheaths of the central nervous system (CNS) and the peripheral nervous system (PNS) are broadly similar. The molecular control of myelination by OL overlaps to a large extent. oligodendrocytes) and SC myelinating (Schwann cells). "

In the laboratory, Monk and his team experimented with zebrafish. In genetic screening and testing, they noted that some zebrafish have more myelin than others. It was discovered that these zebrafish contained a mutation in a gene called FBXW7. The team then removed this particular gene from mice in their labs. The mice had a similar myelin content and this time the myelin was provided by the Schwann cells of the body. Monk explained: "This highlights a very plastic potential for these cells," which means that when oligodendrocytes no longer function, Schwann cells are able to intervene. The authors of the study wrote: "FBXW7 Mutant Schwann cells (Schwann cells) form thicker myelin sheaths and sometimes appear to myelinate multiple axons badogously to oligodendrocytes. "

Monk explained that vertebrates (vertebral animals), jaws, and myelin-producing cells, such as Schwann cells and oligodendrocytes, appear almost simultaneously during fetal development. Among invertebrates, there is no myelin sheath. Giant squids, for example, have thicker axons instead of the myelin sheath, which speeds up the transmission of nerve signals. Monk explained that, to achieve similar goals, "we could have evolved this way, but our spine would have the diameter of a giant sequoia."

Those who have the spine or vertebrates have instead developed a myelin sheath around their nerves to accelerate nerve conduction. Schwann cells can produce myelin around a single axon in the peripheral nervous system, while oligodendrocytes act on multiple axons simultaneously in the brain and spinal cord to protect them from myelin sheaths. "Real estate is fundamentally different in the central nervous system than in the peripheral nervous system," explained Monk. Thus, while Schwann cells are designed to repair each cell one at a time after an injury, they must evolve to work accurately and adapt to conditions such as nerve damage to the peripheral nervous system. On the other hand, lesions in the brain and spinal cord are rarely reversible and, therefore, oligodendrocytes are not as adaptable to changes. Monk simply explained, "There is no selective pressure in the repair of myelin damage in the central nervous system because you will probably die."

Oligodendrocytes form insulating sheaths of myelin around axons of neurons in the central nervous system. Myelin increases the pulse rate and decreases the capacity of the axonal membrane. 3D rendering – Illustration Credit: Juan Gaertner / Shutterstock

This new study may, however, mean that Schwann cells could help repair myelin in the brain and spinal cord. Monk declared as follows: nervous system. "