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ObjectiveHippocampal demyelination, a common feature of postmortem multiple sclerosis (MS) brains, reduces neuronal gene expression and is a likely contributor to the memory impairment that is found in >40% of individuals with MS. How demyelination alters neuronal gene expression is unknown.MethodsTo explore whether loss of hippocampal myelin alters expression of neuronal microRNAs (miRNAs), we compared miRNA profiles from myelinated and demyelinated hippocampi from postmortem MS brains and performed validation studies.ResultsA network-based interaction analysis depicts a correlation between increased neuronal miRNAs and decreased neuronal genes identified in our previous study. The neuronal miRNA miR-124 was increased in demyelinated MS hippocampi and targets mRNAs encoding 26 neuronal proteins that were decreased in demyelinated hippocampus, including the ionotrophic glutamate receptors AMPA2 and AMPA3. Hippocampal demyelination in mice also increased miR-124, reduced expression of AMPA receptors, and decreased memory performance in water maze tests. Remyelination of the mouse hippocampus reversed these changes.InterpretationWe establish here that myelin alters neuronal gene expression and function by modulating the levels of the neuronal miRNA miR-124. Inhibition of miR-124 in hippocampal neurons may provide a therapeutic approach to improve memory performance in MS patients.

The characterization of HMGA1a in vivo posttranslational modification (PTM) patterns found in a nonmetastatic and two metastatic lines of MCF-7 human breast cancer cells of differing tumorigenic potential is focused. PTM types and the amino acids on which they occur are identified by matrix-assisted laser desorption ionization time-of -flight (MALDI-TOF) mass spectrometry.

Natural autoreactive monoclonal IgM antibodies have demonstrated potential as therapeutic agents for central nervous system (CNS) disease. These antibodies bind surface antigens on specific CNS cells, activating intracellular repair-promoting signals. IgM antibodies that bind to surface antigens on oligodendrocytes enhanced remyelination in animal models of multiple sclerosis. IgM antibodies that bind to neurons stimulate neurite outgrowth and prevent neuron apoptosis. The neuron-binding IgM antibodies may have utility in CNS axon- or neuron-damaging diseases, such as amyotrophic lateral sclerosis, stroke, spinal cord injury, or secondary progressive multiple sclerosis. Recombinant remyelination-promoting IgM antibodies have been generated for formal toxicology studies and, after Food and Drug Administration approval, a phase 1 clinical trial. Natural autoreactive monoclonal antibodies directed against CNS cells represent novel therapeutic molecules to induce repair of the nervous system.