myelin

The RhoE protein has been identified as being important for axons’  myelination and extension in the central nervous system, two processes that go awry in diseases like multiple sclerosis (MS). The findings stem from Pilar Madrigal’s doctoral thesis, “Role of the small GTPase RhoE in myelination and axonal tracts development.”…

Subpopulations of oligodendrocytes — cells that produce the myelin sheath that protects nerve fibers — are altered in patients with multiple sclerosis, a study shows. These findings suggest that oligodendrocyte diversity and the different functions of these subpopulations might have a greater role in the disease than previously thought. The severity of MS varies greatly, and the patient's disability level does not correlate well with the degree of myelin loss. This suggests that other factors contribute to MS severity. One such factor may be that oligodendrocytes are heterogeneous — diverse in makeup and function. For example, oligodendrocytes in mouse spinal cords are known to naturally produce longer myelin sheaths than oligodendrocytes in the mouse brain. Additionally, individual oligodendrocytes have been shown to have different molecular makeups. However, the extent of human oligodendrocyte diversity and its possible contribution to MS pathology remains unknown. Researchers from the Karolinska Institutet and the MRC Centre for Regenerative Medicine studied the differences of individual human oligodendrocytes from healthy and MS brains to assess their diversity. Specifically, the team examined oligodendrocytes from the white matter areas of post-mortem human brains both from MS and non-MS patients. The team examined the RNA content — the messenger molecule carrying instructions from DNA for the production of proteins — from individual oligodendrocytes. Researchers identified groups of RNA molecules that defined features of oligodendrocytes from healthy human white matter. Some of these groups match those that defined oligodendrocytes in healthy mice. Strikingly, some of these RNA molecules in healthy brains were under-represented in oligodendrocytes from MS brains, whereas others were more prevalent. “We found that oligodendrocytes are a diverse population of cells and that different types are likely to have different functions in the brain,” Charles ffrench-Constant, the study's co-lead author, said in a Karolinska Institutet news release written by Katarina Sternudd. These differences in oligodendrocyte RNA content may indicate different functional states of oligodendrocytes in MS lesions. “The proportions of different resident oligodendrocytes in the lesions are changed, along with their properties, suggesting that they might have important roles in MS,” said Eneritz Agirre, PhD, a study co-author. Furthermore, the researchers believe that this altered diversity in oligodendrocytes in MS may be important to understand disease progression and develop therapeutic approaches. “Understanding which types of oligodendrocytes are most beneficial in repairing myelin will be crucial for maximizing the chances of developing much-needed treatments for MS,” said Anna Williams, PhD, study co-lead author. The team concluded that the changes in different oligodendrocyte subpopulations in MS suggest "a more complex role of these cells in the pathology of the disease, but also in regeneration of new cells,” said Gonçalo Castelo-Branco, PhD, another study co-lead author.

Endothelial cells, those lining the inside of small blood vessels, promote clearance of myelin debris — a common detrimental outcome of demyelinating diseases such as multiple sclerosis (MS) or spinal cord injury. However, in its path to clear the brain from myelin debris, endothelial cells trigger more damaging mechanisms, promoting…

A genetic variant associated with an increased risk of multiple sclerosis (MS) due to its impact on certain immune system cells can also affect brain cells called astrocytes, a study shows. Reported in the study, “Enhanced astrocyte responses are driven by a genetic risk allele associated with multiple…

The formation of new myelin sheaths by oligodendrocytes is impaired in the absence of a small molecule, called Vav3, that oversees pathways regulating the shape of oligodendrocytes, new study reports. Its researchers pinpoint Vav3 as a potential therapeutic target to improve and speed myelin repair in diseases like multiple sclerosis…

Mature, adult oligodendrocytes can reacquire their ability to produce myelin to replace the ones lost in diseases like multiple sclerosis (MS) without undergoing a stem cell-like state, a new study shows. Myelin is the fat-rich substance that wraps around nerve fiber projections (axons) protecting them and increasing the speed of…

Blocking SARM1, a protein identified as a central mediator of nerve cell degeneration, works to prevent damage to axons — nerve cell fibers essential in cell-to-cell communication — and may be a way of treating neurodegenerative diseases like multiple sclerosis (MS), data from Disarm Therapeutics shows. Specially, genetically deleting…

Environmental changes, such as high temperatures and alterations in salt types and concentrations, trigger structural changes to myelin that may increase the risk of multiple sclerosis (MS), according to a new study. The research, “Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions,” was…

Jonathan Kipnis, the researcher who discovered that lymphatic vessels are important mediators of the underlying molecular mechanism of multiple sclerosis (MS), has received the prestigious Director’s Pioneer Award from the National Institutes of Health (NIH). This prize recognizes researchers who have made important contributions to the development of new…

Lymphatic vessels, the “roads” that work to clear waste material from the brain, can also carry messages that direct immune system attacks against myelin, promoting the onset of multiple sclerosis (MS), new study shows. While the identity of these messages remains unknown, the findings suggest that blocking these signals could…

Remyelination therapies are on the horizon as an innovative multiple sclerosis (MS) treatment, according to my neurologist. These therapies have been on my radar the last few years, but to hear my neurologist say they could soon be a reality makes me hopeful of the possibilities. To offer a…