In a recent study, the Washington University School of Medicine researchers found that immune cells that shield the brain and spinal cord come mainly from the skull.
A Devdiscourse article specified that this finding opens up the possibility of developing treatments to target such cells as a way to avoid or treat brain diseases.
The immune system, as described in the article, is the "best frenemy" of the brain. It shields the brain from infection, not to mention helps injured tissues heal, although it causes autoimmune diseases as well and creates inflammation that initiates neurodegeneration.
A pair of new studies in mice suggest that the two-edged nature of the association between the brain and the immune system may come down to the immune cells' origin that guards the meninges, the tissues surrounding the brain and spinal cord.
Immune Cells Coming from the Skull's Bone Marrow
In the complementary research, Skull and vertebral bone marrow are myeloid cell reservoirs for the meninges and CNS parenchyma, published in the Science journal, two teams of researchers from the Washington School of Medicine in St. Louis unexpectedly discovered that a lot of the immune cells in the meninges are come from bone marrow in the skull and travel to the brain through special channels minus passing through the blood.
Such skull-derived immune cells are described to be peacekeepers dedicated to keeping a healthy current condition. The other immune cells, the ones that come from the bloodstream, appear to be the troublemakers.
They transport genetic signatures that mark them as possible to promote autoimmunity and inflammation, and they turn out to be more abundant with aging or under occurrences of injury or disease.
Taken together, the results showed a key aspect of the link between the immune system and the brain that could inform the understanding of a wide range of brain conditions.
Potential Treatment for Brain Disorders
According to Alan A. and Edith L. Wolff, Distinguished Professor of Pathology & Immunology, Jonathan Kipnis, PhD, there has been this gap in their knowledge that's applicable to nearly every neurological disease like Alzheimer's disease, neuro-COVID, brain injury and multiple sclerosis, among others.
Kipnis, a BJC investigator and one of the papers' senior author added, they knew immune cells were involved in neurological conditions, although they didn't know where they were coming from.
According to a similar report from the ScienceDaily, What they have found, he added, is that there is a new source that has been described previously for the said cells. Earlier this year, the senior author showed that immune cells located in the meninges keep tabs on the brain.
As part of this new research, Kipnis, and Robert Brock Belliveau, MD, Professor of Pathology and the senior author on the paper Marco Colonna MD, independently launched projects to discover where such cells are coming from.
Kipnis focused on the inherent arm of the immune system. Colonna, on the other hand, focused on the adaptive arm.
Inherent immune cells are responsible for inflammation, helping defend from infection and treat injuries, although they can impair tissues and add to degenerative conditions like Alzheimer's and Parkinson's diseases.
Adaptive immune cells can specifically target undesirables like viruses and tumors, although they can mistakenly home in as well, on the own healthy tissues of the body, leading to autoimmune diseases like multiple sclerosis, among others.
Colonna, together with his colleagues, which include co-first authors postdoctoral researcher Simone Brioschi, Ph.D.; postdoctoral researcher Wei-Le Wang, Ph.D.; and graduate student Vincent Peng traced the development of B cells, described in the British Society for Immunology the adaptive immune system's antibody-producing members.
As a result, the researchers discovered that most B cells in the meninges arose and matured in the bone marrow of the skull.
As B cells mature, they need to be taught to determine between normal proteins from the body, which postures no treat, and foreign proteins that indicate infection or illness, not to mention necessitate a response.
Colonna, also a professor of medicine explained, B cells in the skull's bone marrow come into contact with the central nervous system. More so, they are informed by the central nervous system.
It would not be possible, he elaborated, if they were released into the blood. Since they are directly in contact with the brain, they learn to be tolerant of brain proteins.
Related information is shown on The Noted Anatomist's YouTube video below:
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