Prion protein participates in the regulation of classical and alternative activation of BV2 microglia

摘要

The cellular prion protein (PrPC) is a glycoprotein anchored by glycosylphosphatidylinositol (GPI) to the cell surface and is abundantly expressed in the central nervous system. Numerous studies have suggested a protective function for PrPC, including protection from ischemic and excitotoxic lesions and several apoptotic insults, and recent reports have shown that PrPC has a context-dependent neuroprotective function. In this study, we investigated the effect of PPNP down-regulation on various forms of microglial activation. We first examined the mRNA expression of PRNP upon exposure to IFN-γ, IL-4, or IL-10 in BV2 microglia. We then analyzed the effect of si-RNA-mediated disruption of PRNP on different parameters of microglial activation in IFN-γ-, IL-4-, or IL-10-stimulated microglia. The results showed that PRNP mRNA expression was invariably down-regulated in microglia upon exposure to IFN-γ, IL-4, or IL-10. PRNP silencing prior to cytokines treatment reduced the responsiveness of microglia to INF-γ treatment, significantly altered IL-4-induced microglial activation phenotype, and had no effect on IL-10-induced microglial activation. Together, these results support a role of PrPC in the modulation of the shift of microglia from a quiescent state to an activated phenotype and in the regulation of the microglial response during classical and alternative activation. Prion protein regulates classical and alternative activation of microglia Earlier studies have suggested that cellular prion protein has a neuro-protective function. In this study, we demonstrated that cellular prion protein is involved in the modulation of the shift of microglia from a quiescent phenotype to an activated state and in the regulation of the microglial response during classical and alternative activation. The result provides the basic data for further study of cellular prion protein context- dependen neuro-protective function.