OHSU research could lead to new treatments to cure disorders of the nervous system: MEDICINE AND HEALTH: Science Times

In a study published in the journal Nature CommunicationsResearchers have discovered that a particular type of cell produces a protective sheath covering nerve fibers much more prolific than previously thought. When they had the revelation on Schwann cells, this suggests new ways to treat nerve damage and various forms of neuropathy. Additional research may prove useful for promoting myelin repair in central nervous system disorders such as multiple sclerosis, where myelin lesions slow down or block electrical signals from the brain.

As lead author of the study, Kelly Monk, Ph.D., professor and co-director of the Vollum Institute of Oregon Health & Science University, this discovery upsets the clbadic definition of cell function from Schwann.

The two types of cells in the body that produce myelin are oligodendrocytes in the brain and spinal cord, and Schwann cells in the rest of the body. Until recently, scientists thought that only oligodendrocytes generated several myelin sheaths around axons, the thin projection of a nerve cell that carried electrical signals between cells. In new research, the team discovered that Schwann cells are also able to spread myelin on several axons.

The team heard the news after performing a genetic screening of zebrafish in the Monk Lab. They identified fish with more myelin than expected, and these fish carried a mutation in a gene called fbxw7. When they neutralized the gene in genetically modified mice, they discovered an unexpected feature, such that individual Schwann cells began to spread myelin in many axons. According to Monk, this highlights a very plastic potential for these cells.

In the history of evolution, Schwann cells and oligodendrocytes appeared at the same point, with the appearance of jaws in the vertebrate lineage. Invertebrates lack myelin and some, such as modern squid, use thick axons to rapidly transmit signals between neurons. Monk noted that they could have evolved this way, but that their spine would have the diameter of a giant sequoia.

In contrast, remyelinization in the central nervous system tended to be an evolutionary impbade since few would have survived violent shock to the brain or spine. Monk explained that there was no selective pressure in the repair of damage caused by myelin in the central nervous system because you will probably die. However, the discovery released by the researchers suggests a new opportunity to heal the brain and spine. Monk concluded that targeting the fbxw7 gene, or molecules in the downstream pathway, could be a powerful way to promote myelin repair in the central nervous system.