Cellular distribution of proteasomes and immunoproteasomes in the cerebellum of mice with chronic experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a severe neuroinflammatory disorder characterized by the loss of myelin around the axons of the central nervous system. Experimental autoimmune encephalomyelitis (EAE) is a commonly used animal model of MS that recapitulates the various stages of the disease. Our laboratory has recently discovered that oxidized proteins accumulate in the cerebellum of mice with chronic EAE, and this seems to be the result of diminished levels of proteasomes, the proteolytic machinery responsible for their degradation. The build-up of oxidized proteins is toxic to cells and thought to play a role in the pathophysiology of MS and EAE. I am currently trying to determine whether the reduction in the levels of standard proteasome levels (as measured by the catalytic β5 subunit) and immunoproteasomes (as measured by the catalytic iβ5 subunit) is a generalized phenomenon or it occurs in particular cell types. To this end, I have learned and optimized a double-immunohistochemistry (IHC) technique that uses anti-β5 (or iβ5) antibodies and cell-specific antibodies. This approach will allow me to determine the relative amounts of proteasomes and immunoproteasomes in neurons, oligodendrocytes and astrocytes in the cerebellum of EAE animal model in the chronic phase of the disease. This will help to gain insights into the relationship between proteasomal dysfunction and tissue damage in this disease. Work supported by IMSD and R01 NS057755 from NIH.