So we first need to find out from our doctors if loss of myelin occurs during a stroke.
Scientists at Mainz University identify inhibitor of myelin formation in the central nervous system
Possible implication for various neurological illnesses
Scientists at the Mainz University Medical Center have discovered
another molecule that plays an important role in regulating myelin
formation in the central nervous system. Myelin promotes the conduction
of nerve cell impulses by forming a sheath around their projections, the
so-called axons, at specific locations – acting like the plastic
insulation around a power cord. The research team, led by Dr. Robin
White of the Institute of Physiology and Pathophysiology at the
University Medical Center of Johannes Gutenberg University Mainz,
recently published their findings in the prestigious journal EMBO
reports.
Complex organisms have evolved a technique known as saltatory
conduction of impulses to enable nerve cells to transmit information
over large distances more efficiently. This is possible because the
specialized nerve cell axonal projections involved in conducting
impulses are coated at specific intervals with myelin, which acts as an
insulating layer. In the central nervous system, myelin develops when
oligodendrocytes, which are a type of brain cell, repeatedly wrap their
cellular processes around the axons of nerve cells forming a compact
stack of cell membranes, a so-called myelin sheath. A myelin sheath not
only has a high lipid content but also contains two main proteins, the
synthesis of which needs to be carefully regulated.
The current study analyzed the synthesis of myelin basic protein
(MBP), a substance which is essential for the formation and
stabilization of myelin membranes. In common with all proteins, MBP is
generated in a two-stage process originating from basic genetic material
in the form of DNA. First, DNA is converted to mRNA, which, in turn,
serves as a template for the actual synthesis of MBP. During myelin
formation, the synthesis of MBP in oligodendrocytes is suppressed until
distinct signals from nerve cells initiate myelination at specific
"production sites". To date, the mechanisms involved in the suppression
of MBP synthesis over relatively long periods of time have not been
understood. This is where the current work of the Mainz scientists comes
in, as they were able to identify a molecule that is responsible for
the suppression of MBP synthesis.
"This molecule, called sncRNA715, binds to MBP mRNA, thus preventing
MBP synthesis," explains Dr. Robin White. "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."
Understanding the molecular basis for myelin formation is essential
with regard to various neurological illnesses that involve a loss of the
protective myelin layer. For example, it is still unclear why
oligodendrocytes lose their ability to repair the damage to myelin in
the progress of multiple sclerosis (MS). "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," Robin White continues. "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."
No comments:
Post a Comment