Molecluar mechanism of propagation of abnormal prion protein in the cells

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In this research, we studied on the molecular mechanism of prion propagation in the cells through analyses of the effect of compounds that inhibit PrP^<Sc> formation and identification of host factor(s) and microenvironment that are involved in prion propagation.Four different anti-PrP antibodies that react with PrP^C on the cell surface inhibited PrP^<Sc> formation in cells persistently infected with prion. The antibody-PrP^C complex on the cell surface was not internalized efficiently and tended to retain on the cell surface. These results suggest that anti-PrP mAb antagonized PrP^<Sc> formation by interfering with the regular PrP^C degradation pathway. In addition, we screened synthesized sulfated glycosides for the inhibition of PrP^<Sc> formation and found 4-sulfo-N-acetylglucosamie and 6-sulfo-N-acetylglucosamine inhibited PrPSc formation in prion-infected cells. These sulfated glycosides accelerated the endocytosis of PrP^C and reduced a total amount of PrP^C, while sulfated gly … More cosides that were not inhibited PrP^<Sc> formation did not reduce the total amount of PrP^C. These results indicated that sulfated glycosides and glycosaminoglycans inhibited PrP^<Sc> formation by facilitating the degradation of PrP^C.We established subclones of Neuro2a (N2a) mouse neuroblastoma cells and distinguished prion-susceptible and non-susceptible subclones. One non-susceptible subclone, N2a-1, expressed PrP^C as the same level as parental N2a and other prion-susceptible subclones. There was no difference in the binding of PrP^<Sc> to the susceptible and non-susceptible subclones. Presence of N2a-1, which expresses PrP^C but is resistance to prion propagation, indicated the involvement of host factors other than PrP^C in prion propagation. To identify such host factors, the gene expression profiles between N2a subclones were analyzed by DNA microarray. We selected 36 and 18 genes, which expressed more than two-fold in prion susceptible subclone N2a-5 and prion resistant subclone N2a-1, respectively. We assessed the influence of these genes on prion susceptibility by reducing the gene expression by siRNA technique and found that siRNA against F2, Al, and C5 genes inhibited prion propagation in prion-infected N2a-5 cells. Less