alpha-synuclein is developmentally expressed in cultured rat brain oligodendrocytes

Although a neuronal protein, alpha-synuclein is a major component of glial cytoplasmic inclusions (GCIs) in oligodendrocytes of multiple system atrophy (MSA) brains. Because alpha-synuclein has not been identified in oligodendrocytes of normal brains, we examined cultured rat brain oligodendrocytes during in vitro development and showed that alpha-synuclein mRNA and protein are present in cultured oligodendrocytes. The expression of alpha-synuclein was developmentally regulated; it increased to peak levels at 2 or 3 days in culture but declined thereafter. Indirect immunofluorescence further shows that alpha-synuclein was localized predominantly in cell bodies and primary processes of oligodendroglia. Thus, GCIs may be a consequence of altered rather than de novo expression of alpha-synuclein in MSA oligodendrocytes.