Role of Erk1/2 activation in prion disease pathogenesis: absence of CCR1 leads to increased Erk1/2 activation and accelerated disease progression.

Abstract

Prion diseases are neurodegenerative infections with gliosis and vacuolation. The mechanisms of degeneration remain unclear, but chemokines may be important. In current experiments CCR1 knock-out (KO) mice succumbed more rapidly to scrapie infection than WT controls. Infected KO mice had upregulation of CCL3, a CCR1 ligand, and CCR5, a receptor with specificity for CCL3. Both infected KO and WT mice had upregulation of CCR5-mediated signaling involving activation of Erk1/2 in astrocytes; however, activation was earlier in KO mice suggesting a role in pathogenesis. In both mouse strains activation of the Erk1/2 pathway may lead to astrocyte dysfunction resulting in neurodegeneration.