Myelin-making Schwann cells have an ability every aging Hollywood star would envy: they can become young again. According to a study appearing in the May 19 issue of the Journal of Cell Biology, David B. Parkinson (University College London, London, UK) and collogues have pinned down a protein that returns the cells to their youth, a finding that might help researchers understand why myelin production falters in some diseases.

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LOMA LINDA – Abbey Umali does not care if she comes in last place.
The 9-year-old girl is just happy to compete in the sixth annual PossAbilities Triathlon today at Loma Linda University.
Abbey – who has a rare form of muscular dystrophy – will compete against other able-bodied athletes in her age group.
“First, we run, then we bike, then we swim,” said Abbey, the Muscular Dystrophy Association’s 2008 National Goodwill Ambassador. “It’s really fun.”

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Glia. 2008 Feb;56(3):306-17.
Developmental loss of NT-3 in vivo results in reduced levels of myelin-specific proteins, a reduced extent of myelination and increased apoptosis of Schwann cells.
Woolley AG, Tait KJ, Hurren BJ, Fisher L, Sheard PW, Duxson MJ.
Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
This work investigates the role of NT-3 in peripheral myelination. Recent articles, based in vitro, propose that NT-3 acting through its high-affinity receptor TrkC may act to inhibit myelin formation by enhancing Schwann cell motility and/or migration. Here, we investigate this hypothesis in vivo by examining myelination formation in NT-3 mutant mice. On the day of birth, soon after the onset of myelination, axons showed normal ensheathment by Schwann cells, no change in the proportion of axons which had begun to myelinate, and no change in either myelin thickness or number of myelin lamellae. However in postnatal day 21 mice, when myelination is substantially complete, we observed an unexpected reduction in mRNA and protein levels for MAG and P(0), and in myelin thickness. This is the opposite result to that predicted from previous in vitro studies, where removal of an inhibitory NT-3 signal would have been expected to enhance myelination. These results suggest that, in vivo, the importance of NT-3 as a major support factor for Schwann cells (Meier et al., (1999) J Neurosci 19:3847-3859) over-rides its potential role as an myelin inhibitor, with the net effect that loss of NT-3 results in degradation of Schwann cell functions, including myelination. In support of this idea, Schwann cells of NT-3 null mutants showed increased expression of activated caspase-3. Finally, we observed significant reduction in width of the Schwann cell periaxonal collar in NT-3 mutant animals suggesting that loss of NT-3 and resulting reduction in MAG levels may alter signaling at the axon-glial interface.