Expression of alpha-synuclein in a human glioma cell line and its up-regulation by interleukin-1beta.

Although alpha-synuclein is expressed primarily in neurons, it is a major component of oligodendroglial and astrocytic inclusions in several neurodegenerative diseases. Recent study has further demonstrated that alpha-synuclein is expressed in cultured rat oligodendrocytes. We determined whether alpha-synuclein might be expressed in astrocytic cells. alpha-Synuclein mRNA and protein were detected in U251 human astrocytic glioma cells and normal human astrocytes, and the levels were increased in the former, but not in the latter, by stimulation with interleukin-1beta in a time- and concentration-dependent manner. Serum deprivation also led to an increase of alpha-synuclein mRNA and protein in U251 cells. Immunofluorescent staining confirmed the cell-associated alpha-synuclein. These findings suggest that human astrocytes can produce alpha-synuclein in culture and that certain inflammatory cytokines and cell stress increase alpha-synuclein expression.