Corpora amylacea from multiple sclerosis brain tissue consists of aggregated neuronal cells

In this report, we describe proteomic analysis of corpora amylacea collected by postmortem laser microdissection from multiple sclerosis (MS) brain lesions. Using low level protein loads (about 30 microg), a combination of two-dimensional electrophoresis with matrix-assisted laser desorption/ionization-time of flight mass spectrometry and database interrogations we identified 24 proteins of suspected neuronal origin. In addition to major cytoskeletal proteins like actin, tubulin, and vimentin, we identified a variety of proteins implicated specifically in cellular motility and plasticity (F-actin capping protein), regulation of apoptosis and senescence (tumor rejection antigen-1, heat shock proteins, valosin-containing protein, and ubiquitin-activating enzyme E1), and enzymatic pathways (glyceraldehyde-3-dehydrogenase, protein disulfide isomerase, protein disulfide isomerase related protein 5, lactate dehydrogenase). Samples taken from regions in the vicinity of corpora amylacea showed only traces of cellular proteins suggesting that these bodies may represent remnants of neuronal aggregates with highly polymerized cytoskeletal material. Our data provide evidence supporting the concept that biogenesis of corpora amylacea involves degeneration and aggregation of cells of neuronal origin.