Modulation of the α 2 macroglobulin receptor/low density lipoprotein receptor related protein by interferon- γ in human astroglial cells

Alpha 2macroglobulin receptor/low density lipoprotein receptor-related protein ( α 2Mr/LRP) is a multi-functional cell surface receptor that has been implicated in important processes, such as atherogenesis, cellular migration, immune response and degenerative diseases. Its expression increases in human brain during Alzheimer's disease, tissue injury and neoplastic transformation. In the present paper we studied the regulation of α 2Mr expression by interferon- γ (IFN γ) in human astrocytoma cell lines and in fetal astrocytes. Western blots demonstrated an increase of the α 2Mr expression after 24 h of IFN γ treatment. This effect paralleled the up-regulation of α 2Mr mRNA, as detected by PCR. By prolonging incubation with IFN γ, we observed a decrement of α 2Mr in IFN γ treated cells, both by western blot and cytometric analysis. Since in the same cells IFN γ also up-regulates α 2 macroglobulin, this effect may be due to an augmented degradation of the receptor during its recycling.