In the war against diseases, nerve cells need their armorNovember 13, 2008Scientists find key step in maintaining myelin In a new study, researchers at the Montreal Neurological Institute (MNI), McGill University, and the Université de Montréal have discovered an essential mechanism for the maintenance of the normal structure of myelin, the protective covering that insulates and supports nerve cells (neurons). Up until now, very little was known about myelin maintenance. This new information provides vital insight into diseases such as Multiple Sclerosis (MS) and other progressive demyelinating diseases in which myelin is destroyed, causing irreversible damage and disrupting the nerve cells' ability to transmit messages. The research, published recently in the Journal of Neuroscience, is the first to identify a role for the protein netrin-1, previously characterized only in the developing nervous system, with this critical function in the adult nervous system. This research was funded by the MS Society of Canada and the Canadian Institutes of Health Research. Netrin-1, a protein deriving its name from the ancient Indian language, Sanskrit, word for 'one who guides,' is known to guide and direct nerve cell axons to their targets. In the molecular biological studies conducted by the team, they found that blocking the function of netrin-1 and one of its receptors in adult neural tissue causes the disruption of myelin. "We've known for just over 10 years that netrin is essential for normal development of the nervous system, and we also knew that netrin was present in the adult brain, but we didn't know why. It is fascinating that netrin-1 has such a vital role in maintaining the structure of myelin in the adult nervous system," says Dr. Tim Kennedy, a neuroscientist at the MNI and the senior investigator of this study, "continuing to pursue the implications of that are incredibly exciting." "Our mission is to find a cure as quickly as possible and enhance quality of life," says Karen Lee, assistant vice-president of research programs for the MS Society of Canada. "We are pleased to be involved in funding work that supports our mission and feel that this research takes us closer to understanding the players and processes that could aid in remyelination."
The results of this study, a collaboration between Dr. Kennedy's laboratory, clinician-scientists in the Neuroimmunology group at the MNI headed by Dr. Jack Antel, and Dr. Adriana Di Polo's laboratory at the Université de Montréal, are especially significant in Canada which has one of the highest rates of Multiple Sclerosis (MS) in the world with approximately 1,000 new cases of MS diagnosed each year. ''This is an exciting new area of research that could lead to new treatment strategies and ultimately improve the life of the people who suffer from MS. We are proud to be funding this collaborative research between basic and clinician-scientists," said Dr. Rémi Quirion, Scientific Director of the CIHR Institute of Neurosciences, Mental Health and Addiction. MS is a disease of the central nervous system in which myelin is destroyed. Understanding the factors involved in maintaining myelin and promoting remyelination, offers new therapeutic targets and avenues for the treatment of MS. As described by Dr. Jack Antel, "Current MS therapies aim to block inflammation. In order to protect and restore myelin it is essential to to understand the molecules involved in these processes. This is the new era of the neurobiology of MS." The team is taking the investigation further by teaming up with the MS clinic and doctors at the MNI, providing access to a huge amount of patient data, and enabling them a broader clinical perspective. Importantly, this newly discovered mechanism implicates a cascade of protein molecules that have not been known to be involved in myelination. The study was carried out in mice and using in vitro cell cultures. The investigators found that myelin develops normally, but then begins to come apart. Interestingly, in some respects this mirrors what happens in some demyelinating diseases like MS, where myelin forms and may be stable for years, but is then disrupted and begins to fail. Specifically, the new findings show that netrin-1 and its receptor are needed to hold paranodal junctions in place, and thereby maintain the structure of myelin. The paranodal junction is a highly specialized region of contact where an oligodendrocyte cell attaches itself to the nerve cell's axon. This juncture acts as a molecular fence, which organizes and segregates the distribution of key proteins along the nerve cells axon and plays an imperative role in the proper conduction of electrical signals along the length of the nerve cell. When the function of netrin-1 and its receptor is disrupted, the organization of this adhesive junction comes apart, disrupting the function of nerve cells in the brain and spinal cord. Montreal Neurological Institute and Hospital Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. Cancer Detection Bird Flu Gastric Bypass Ebola Lifespan Rhinovirus Risky Behavior Plastic Surgery Lung Disease Cardiac Arrest Mammograms Flu Virus Human Evolution Parkinson’s Disease Archaea Nanowire Computer Chip Amniotic Fluid CPR Oxidative Stress Snoring Gastric Cancer Urinary Tract Infection Biomass Junk DNA
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Related Myelin Current Events and Myelin News Articles New clue into how brain stem cells develop into cells which repair damaged tissue The joint research, funded by the National Multiple Sclerosis Society and the UK MS Society as well as the National Institutes of Health and Howard Hughes Medical Institute, was conducted by scientists at the University of California San Francisco (UCSF) and University of Cambridge and was published today (01 July) in the journal Genes and Development. MS study offers theory for why repair of brain's wiring fails Scientists have uncovered new evidence suggesting that damage to nerve cells in people with multiple sclerosis accumulates because the body's natural mechanism for repair of the nerve coating called "myelin" stalls out. Neural stem cell differentiation factor discovered Neural stem cells represent the cellular backup of our brain. These cells are capable of self-renewal to form new stem cells or differentiate into neurons, astrocytes or oligodendrocytes. Scripps research scientists observe human neurodegenerative disorder in fruit flies A team of scientists from The Scripps Research Institute, Katholeike Universiteit Leuven, and the University of Antwerp, Belgium, among other institutions, has created a genetically modified fruit fly that mimics key features of Charcot-Marie-Tooth disease, a common neurodegenerative disorder that strikes about one out of every 2,500 people in the United States. UCF team's advanced nerve cell system could help cure diabetic neuropathy, related diseases Multiple sclerosis, diabetic neuropathy, and other conditions caused by a loss of myelin insulation around nerves can be debilitating and even deadly, but adequate treatments do not yet exist. One size does not fit all Statins, a commonly prescribed class of drugs used by millions worldwide to effectively lower blood cholesterol levels, may actually have a negative impact in Multiple Sclerosis (MS) patients treated with high daily dosages. Human ES cells progress slowly in myelin's direction Scientists from the University of Wisconsin, USA, report in the journal Development the successful generation from human embryonic stem cells of a type of cell that can make myelin, a finding that opens up new possibilities for both basic and clinical research. Mayo researchers discover mechanism of cell type-specific signaling in tumor development Mayo Clinic researchers have discovered the mechanisms behind two key checkpoints in cell growth and development - factors that may ultimately allow investigators to benchmark progression of tumor cells or stop them from further development. The findings appear in the current online issue of Developmental Cell. Avastin effective at delaying brain tumor progression in recurrent disease The use of Avastin alone to treat a subgroup of recurrent Grade 3 brain tumors showed it was safe and effective at delaying tumor progression, according to a retrospective study of 22 patients conducted by a researcher at the Seattle Cancer Care Alliance. Study gives more proof that intelligence is largely inherited They say a picture tells a thousand stories, but can it also tell how smart you are? Actually, say UCLA researchers, it can. More Myelin Current Events and Myelin News Articles |
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