myelin

Two new studies delve into the structure of SARM1, an enzyme that plays a key role in nerve cell degeneration, and are expected to aid the development of targeted therapies for neurodegenerative disorders such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and peripheral neuropathies. SARM1…

A new study demonstrates that intracellular sigma peptide (ISP) can promote remyelination in a mouse model of multiple sclerosis (MS). Importantly, this study was independent of NervGen, a pharmaceutical company that is developing an ISP-like compound — NVG-291 — for the treatment of nerve injury and MS. The study,…

NervGen wants to advance the development of NVG-291, its lead investigational therapy for spinal cord damage, as a potential remyelination treatment for multiple sclerosis (MS), the company announced. Following preclinical data showing that NVG-291 promotes myelin repair and regeneration of damaged nerves in animal models of…

Editor’s note: “Need to Know” is a series inspired by common forum questions and comments from readers. Have a comment or question about MS? Visit our forum. This week’s question is inspired by the forum topic “How the Blood Brain Barrier May Thwart MS Progression” from Feb. 9, 2017. What…

Exosomes — tiny vesicles secreted by cells — collected from bone marrow stem cells and injected into a mouse model of multiple sclerosis (MS) helped to treat the disease, a study reports. Specifically, this treatment eased myelin loss and neuroinflammation in the mice, and improved motor function, the…

Giving estrogen to two different adult mouse models of multiple sclerosis (MS), including the experimental autoimmune encephalomyelitis (EAE) model, promoted remyelination, a new study shows. Exposure to the hormone affected gene activity in oligodendrocytes, tricking them into producing myelin (the fatty substance that protects nerve cells, and that is destroyed…

Cellular senescence — the process of aging at the cellular level — may play a role in the development of primary progressive multiple sclerosis (PPMS) by limiting the ability of myelin-producing cells (oligodendrocytes) to renew and mature. The study with that finding, “Cellular senescence in progenitor…

Oligodendrocyte precursor cells (OPCs), the cells responsible for myelin production, are unable to migrate into sites of myelin loss in the brain. These cells then cluster and disrupt the blood-brain barrier (BBB), triggering an inflammatory process in the early stages of multiple sclerosis (MS), a study shows. The study, “Aberrant oligodendroglial–vascular interactions disrupt the blood–brain barrier, triggering CNS inflammation,” was published in the journal Nature Neuroscience. MS is an autoimmune disease characterized by the loss of myelin (demyelination) — the fat-rich substance that protects nerve fibers — which leads to neurodegeneration. Along with loss of myelin, researchers have observed that the blood-brain barrier — a highly selective membrane that shields the central nervous system with its cerebrospinal fluid from the general blood circulation — breaks down in the initial stages of disease. A team led by researchers at the University of California, San Francisco, have now discovered that OPCs are involved in the disruption of the blood-brain barrier in MS, according to a press release from the National MS Society, which funded the study. Oligodendrocytes are myelin-producing cells and are responsible for myelinating the nerve cells’ axons — a single oligodendrocyte is capable of myelinating multiple axons. Mature myelin-producing oligodendrocytes develop from more immature, stem cell-like OPCs. In a normal brain, upon myelin loss, OPCs are called into action and travel into the damage site where they mature and generate myelin-producing oligodendrocytes. In this study, the researchers found that OPCs in MS form clusters in blood vessels of the brain-blood barrier, having lost the ability to detach from these vessels and migrate to injury sites. In an animal model of MS, they saw that OPC aggregates altered the location of other cells — called astrocytes — in a competition for space, and contributed to the disruption of blood vessels. Astrocytes are a group of star-shaped cells, belonging to the group of glial cells, that provide neurons with energy, and work as a platform to clean up their waste. They also have other functions within the brain, such as regulating blood flow and inflammation. The team also observed that OPC aggregates trigger an immune inflammatory response, shown by a large number of microglia (the central nervous system immune cells) and immune cells called macrophages around these cell clusters. “We find in several MS cases, in lesion areas with active inflammation, that OPCs can be found clustered on vasculature, representing a defect in single cell perivascular migration and inability to detach from blood vessels,” the researchers wrote. Further molecular analysis revealed that OPCs have high levels of Wnt signaling, and elevated secretion of Wif1 factor to the extracellular space that could explain why OPCs accumulate and destroy the blood-brain barrier. The WiF1 factor is actually a negative regulator of Wnt signaling that is essential for the maintenance of the blood-brain barrier structure. This factor competes with Wnt ligands, and affects the integrity of cellular junctions, making the blood-brain barrier more fragile and permeable. "Evidence for this defective oligodendroglial–vascular interaction in MS suggests that aberrant OPC perivascular migration not only impairs their lesion recruitment but can also act as a disease perpetuator via disruption of the BBB,” the researchers wrote. They suggested that more studies are needed to better understand the interactions between blood vessels and oligodendrocytes, which could help identify new therapeutic targets for promoting myelin repair in MS.

A protein that promotes nervous system repair through remyelination — the creation of myelin, the protective sheath around nerve cells — in mice also is found in remyelinating plaques in brains of multiple sclerosis (MS) patients, new research shows. This protein potentially represents a new therapeutic target in demyelinating…

Two-year treatment with temelimab reduced brain atrophy, or shrinkage, preserved myelin, and reduced disease progression in patients with relapsing-remitting multiple sclerosis (RRMS), according to findings from an extension study of a Phase 2b clinical trial. Temelimab, previously known as GNbAC1, is a monoclonal antibody that neutralizes the MS-associated human…

Editor’s note: “Need to Know” is a series inspired by common forum questions and comments from readers. Have a comment or question about MS? Visit our forum. This week’s question is inspired by the forum topic “New MS Therapy Company to Focus on Rejuvenating Coating…