[Rice Catalyst Issue 14]

Myelin Really Gets
On My Nerves
UNDERSTANDING MYELINATION TO
TREAT NEURODEGENERATIVE DISORDERS
BY SEOJIN KWON
Neurons are the cells within our brains
and nerves that allow us to interact
with and understand the world
around us. From the dendrites of the cell
body that receive signals, to the axons that
carry them, and finally, the axon terminals
that send them further, neurons are the
messengers that send information all
throughout our bodies. This allows us to
breathe, talk, eat, and even think. However,
there are billions of cells in our brain
that are often forgotten and overlooked
but equally as vital to the function of our
nervous system: glial cells. [1]
Also known as the glue of the nervous
system, glial cells have a number of
functions that help support, maintain, and
develop the neurons of both the central
(CNS) and peripheral nervous systems
(PNS). The oligodendrocyte, in particular, is
a type of glial cell that plays the crucial role
of creating myelin sheaths around neurons
of the CNS. Myelin sheaths are layers of
proteins and lipids wrapped around axons
that insulate the electrical signals neurons
send to one another for communication,
allowing for the efficient transmission
of signals. Due to the significance of the
myelination process, there are disastrous
effects when it is disrupted, one possibility
being the autoimmune disease, multiple
sclerosis (MS). MS causes one’s body to
attack their own myelin sheaths, disrupting
the communication between the body and
brain. Despite its pivotal importance, the
mechanism for myelination has yet to be
fully understood.
fundamental processes, her lab helps create
new strategies to combat these diseases.
In spite of its complexity, we know that the
myelination mechanism has three distinct
phases of development: (1) oligodendrocyte
progenitor cells (OPC), (2) premyelinating
oligodendrocytes, and (3) myelinating
oligodendrocytes. [2] Initially, OPCs
exist while the oligodendrocyte begins
to extend its branches. After extension
occurs, premyelinating oligodendrocytes
begin to attach to the axons of neurons.
Finally, after fully maturing, myelinating
oligodendrocytes start wrapping the myelin
sheaths around axons.
However, the complex process of
myelination involves several intricate
signaling pathways, which are interactions
between the proteins of a cell that regulates
its functions. Initiating these pathways
requires an environmental stimulus, such
as when a ligand binds to its receptor. Of
these pathways involved in myelination, the
Wnt signaling pathway is one of the main
regulators for oligodendrocyte development
and repair. [3] The activation of the Wnt
signaling pathway has been found to
inhibit the development of oligodendrocyte
differentiation, thus hindering myelin
repair after injury. As such, Dr. Lee believes
that “targeting Wnt pathways will be
beneficial for promoting remyelination in
neurodegenerative disorders.”
To investigate this phenomenon, the
Lee Lab rigorously studied this pathway
Dr. Hyun Kyoung Lee, an associate professor
at the Baylor College of Medicine and
principal investigator at the Jan and Dan
Duncan Neurological Research Institute,
is building the foundation for treating
demyelinating and neurodegenerative
disorders by discovering the molecular
mechanisms and regulatory pathways
for glial cell development and function.
Amidst the dominance of neurons in the
field of neuroscience and the treatment
of neurodegenerative disorders, Dr. Lee
and her lab are working on understanding
“glial-specific function in human health.”
By understanding these complex yet
WORKING MODEL ILLUSTRATING THE ROLE OF DAAM2 IN
REGULATING THE OLIGODENDROCYTE CYTOSKELETON.
OLIGODENDROCYTES ARE A TYPE OF GLIAL CELL THAT PLAYS
A CRUCIAL ROLE OF CREATING MYELIN SHEATHS AROUND
NEURONS OF THE CENTRAL NERVOUS SYSTEM. [5]
1 4 | C A T A L Y S T 2022-2023