Molecule That Inhibits Myelin Formation In The Central Nervous System Discovered

Myelin Formation In The Central Nervous System

According to a study, which was recently published in the journal EMBO reports, researchers at the Mainz University Medical Center of Johannes Gutenberg University have discovered a new molecule the possess an important regulating role in the process of myelin formation in the central nervous system. Myelin is a sheath around dendrites (nerve cell axonal projections) that has an important role in promoting the conduction of nerve cell impulses at specific locations, acting like the plastic insulation around a power cord.

Human nervous system poses a very effective method that confers a feature to nerve cells to transmit information over large distances more efficiently, method known as saltatory conduction of impulses. This technique is possible due to the fact that dendrites involved in impulses transmission are coated at specific intervals with myelin, which has the role to act like an insulating layer. The process of myelin formation begins in the central nervous system when oligodendrocytes, a type of brain cells, wrap their cellular processes around the axons of neurons and form a compact membrane called myelin sheath. Besides a high lipid content, myelin sheath also contains two proteins with a very important function, which synthesis have a very precise regulation process.

In this research, scientists analyzed the synthesis of myelin basic protein (MBP), a compound which posses an essential role in the formation and stabilization of myelin sheath. As all proteins, MBP synthesis is a two-stage process which begins with the synthesis of DNA, the basic genetic material. First step is represented by the conversion of DNA into messenger RNA (mRNA), which serves as a template for the synthesis of MBP. At one specific point, during the process of myelin formation, the synthesis of MBP in olygodendrocytes is stopped until certain molecular signals from nerve cells initiate myelination at specific sites. Until now, the mechanism that inhibit the synthesis of MBP have not been understood but, the current study demonstrates that in this process of suppression a certain molecule is responsible for the inhibition of MBP.

Myelin Sheath

“This molecule, called sncRNA715, binds to MBP mRNA, thus preventing MBP synthesis. Our research findings show that levels of sncRNA715 and MBP inversely correlate during myelin formation and that it is possible to influence the extent of MBP production in oligodendrocytes by artificially modifying levels of sncRNA715. This indicates that the recently discovered molecule is a significant factor in the regulation of MBP synthesis.”, explains Dr. Robin White, the head of the Institute of Physiology and Pathophysiology at the University Medical Center of Johannes Gutenberg University Mainz.

For scientists is very important to understand the molecular basis for the process of myelin formation, because various neurological disorders are the result of the loss of myelin sheath. To date, researchers have not found an explanation why olygodendrocytes lose their propriety to repair damaged myelin as multiple sclerosis (MS) progresses. “Interestingly, in collaboration with our Dutch colleagues, we have been able to identify a correlation between levels of sncRNA715 and MBP in the brain tissue of MS patients.

In contrast with unaffected areas of the brain in which the myelin structure appears normal, there are higher levels of sncRNA715 in affected areas in which myelin formation is impaired. Our findings may help to provide a molecular explanation for myelination failures in illnesses such as multiple sclerosis.”, Dr. Robin White added.