EMP1 and prion disease: Astrocytes stressed in cultures were found to upregulate some PAN reactive markers along with the A1 marker, C3. However, strong downregulation of PAN (Serpina3n), A1 (Serping1), and A2 (Cd109, Emp1) markers [49], which are known to be strongly upregulated in prion diseases [21, 50], questions whether astrocytes isolated from pups and treated in vitro with stressors are able to recapitulate the full spectrum of phenotypic changes associated with prion diseases in mature animals.