Cross-talk between Glial Cells and Relationship in Multiple Sclerosis: An Overview

In medicine, the search for the cause of a disease has been critical to understanding the nature of the
disorder and an important step towards the discovery of effective therapies and prevention. The
search for a cause is more difficult than it may seem at first. For example, even if we find the
mechanism by which the disease progresses, the questions would be: What started the process; then,
if we have found the factors that initiated the process that will lead to questions as to what happened
to this person, and at this very moment. The answer to research questions often raises more
questions and that is how research progresses.
Communication between the immune system and the Central nervous system (CNS), essential for
maintaining homeostasis, is exemplified by cross-talk between glia and neurons. While actively
microglia cells are modulated by neurons in the healthy brain, little is known about the cross-talk
between oligodendrocytes and neurons. Oligodendrocytes, the myelin-forming cells in the CNS, are
essential for the propagation of potentials action along axons, and additionally they serve to support
neurons by neurotropic factors. In demyelinating diseases, such as multiple sclerosis,
oligodendrocytes are thought to be the victims. Also they have strong immune functions, express a
wide variety of innate immune receptors, produce and respond to the chemokines and cytokines and
modulate immune responses. In Addition, they elicit responses that cause progressive
neurodegeneration. Under certain circumstances cells cross the blood brain barrier and reach the
parenchyma, activating a cascade of events culminating in an inflammatory lesion and demyelization.
The main participants of these attacks are the CD4+T cells, antigen presenting glia (microglia and
astrocytes), macrophages and B cells. On the other hand further evidence support that the beginning
of autoimmune response is initiated within the CNS; we should consider other theories to explain not
only multiple sclerosis as an autoimmune disease, and that starts outside the central nervous system.
There is an intimate relationship that we must pay more attention in our research: The dialogue
neuron-glia; the cross-talk between oligodendroglia, microglia and neuron help us to uncover novel
pathways in the brain.