NR AXNE
AU Gilch,S.; Kehler,C.; Schätzl,H.M.
TI Peptide Aptamers Expressed in the Secretory Pathway Interfere with Cellular PrPsc Formation
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.146
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB Prion diseases are rare and obligatory fatal neurodegenerative disorders caused by the accumulation of a misfolded isoform (PrPsc) of the host-encoded prion protein (PrPc). Prophylactic and therapeutic regimens against prion diseases are very limited. To extend such strategies we selected peptide aptamers binding to PrP from a combinatorial peptide library presented on the E. coli thioredoxin A (trx A) protein as a scaffold. In a yeast-two-hybrid screen employing full-length murine PrP (aa 23-231) as a bait we identified three peptide aptamers which reproducibly bind to PrP. Treatment of prion-infected cells with recombinantly expressed aptamers added to the culture medium abolished PrPsc conversion with an IC50 between 350 and 700 nM. For expression in eukaryotic cells, peptide aptamers were fused to a N-terminal signal peptide for entry of the secretory pathway. The C-terminus was either modified by a glycosyl-phosphatidyl-inositol-(GPI) anchoring signal, a KDEL retention motif and the transmembrane and cytosolic domain of LAMP-I, respectively. These peptide aptamers retained their binding properties to PrPc and, depending on peptide sequence and C-terminal modification, interfered with endogenous PrPsc conversion upon expression in prion-infected cells. Notably, infection of cell cultures could be prevented by expression of KDEL peptide aptamers. For the first time, we show that trxA-based peptide aptamers can be targeted to the secretory pathway, thereby not losing the affinity for their target protein. Beside their inhibitory effect on prion conversion, these molecules could be used as fundament for rational drug design.
AD S. Gilch, C. Kehler, H.M. Schätzl, Institute of Virology, Germany
SP englisch
PO Schottland