Insufficient OPC migration into demyelinated lesions is a cause of poor remyelination in MS and mouse models

Failure of remyelination of multiple sclerosis (MS) lesions contributes to neurodegeneration that correlates with chronic disability in patients. Currently, there are no available treatments to reduce neurodegeneration, but one therapeutic approach to fill this unmet need is to promote remyelination. As many demyelinated MS lesions contain plentiful oligodendrocyte precursor cells (OPCs), but no mature myelinating oligodendrocytes, research has previously concentrated on promoting OPC maturation. However, some MS lesions contain few OPCs, and therefore, remyelination failure may also be secondary to OPC recruitment failure. Here, in a series of MS samples, we determined how many lesions contained few OPCs, and correlated this to pathological subtype and expression of the chemotactic molecules Semaphorin (Sema) 3A and 3F. 37 % of MS lesions contained low numbers of OPCs, and these were mostly chronic active lesions, in which cells expressed Sema3A (chemorepellent). To test the hypothesis that differential Sema3 expression in demyelinated lesions alters OPC recruitment and the efficiency of subsequent remyelination, we used a focal myelinotoxic mouse model of demyelination. Adding recombinant (r)Sema3A (chemorepellent) to demyelinated lesions reduced OPC recruitment and remyelination, whereas the addition of rSema3F (chemoattractant), or use of transgenic mice with reduced Sema3A expression increased OPC recruitment and remyelination. We conclude that some MS lesions fail to remyelinate secondary to reduced OPC recruitment, and that chemotactic molecules are involved in the mechanism, providing a new group of drug targets to improve remyelination, with a specific target in the Sema3A receptor neuropilin-1. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00401-013-1112-y) contains supplementary material, which is available to authorized users

Promoting remyelination in multiple sclerosis-recent advances

We review the current state of knowledge of remyelination in multiple sclerosis (MS), concentrating on advances in the understanding of the pathology and the regenerative response, and we summarise progress on the development of new therapies to enhance remyelination aimed at reducing progressive accumulation of disability in MS. We discuss key target pathways identified in experimental models, as although most identified targets have not yet progressed to the stage of being tested in human clinical trials, they may provide treatment strategies for demyelinating diseases in the future. Finally, we discuss some of the problems associated with testing this class of drugs, where they might fit into the therapeutic arsenal and the gaps in our knowledge

Expression of uncoupling protein 3 in mitochondria protects against stress-induced myocardial injury: a proteomic study

It has been confirmed that stress plays an important role in the induction and development of cardiovascular diseases, but its mechanism and molecular basis remain unknown. In the present study, a myocardial injury model induced by restraint stress was established in rat. To screen for the related proteins involved in stress-induced myocardial injury, proteomic techniques based on 2-DE and mass spectrometry were used. In our results, ten proteins were found to be altered. The expression of eight of these proteins was increased after restraint stress, including cardiac myosin heavy chain, dihydrolipoamide succinyltransferase component of 2-oxoglutarate dehydrogenase complex, mitochondrial aldehyde dehydrogenase, H+-transporting ATP synthase, albumin, and apolipoprotein A-I precursor. The expression of uncoupling protein 3 (UCP3) and mitochondrial aconitase was decreased. Most of the proteins were related to energy metabolism. Further research indicated that UCP3 may mediate the myocardial cell response induced by restraint stress