NR AXJM
AU Biocca,S.; Filesi,I.; Cardinale,A.
TI Selective Re-routing of Prion Protein to Proteasomes and Alteration of its Vesicular Secretion Prevent PrPsc Formation
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.49
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Prion diseases are a class of human devastating disorders associated to the conversion of the cellular prion protein (PrPc) into the abnormal scrapie isoform (PrPsc), for which no effective therapeutic strategies exist. Intrabodies represent promising therapeutic agents against conformational diseases in general, because of their virtually infinite capacity to specifically recognize all different conformations of a protein, even the pathological isoforms. Moreover, they have unique advantages since they can target the antigen in different intracellular compartments including extracellular milieu, are highly specific reagents and are very stable in mammalian cells, especially when expressed in the secretory compartment.
ER-retained anti-prion single-chain Fv fragments have been proved to be an effective tool for inhibition of PrPc trafficking to the cell surface and antagonizing PrPsc formation and infectivity (1, 2). In the present study, we have stably expressed the secreted version of the anti-prion 8H4 intrabody (Sec-8H4) in order to compel PrPc outside the cells. In PC12 anti-prion expressing cells, we found that i) PrPc is forced to be degraded by proteasomes; ii) cell surface PrPc level markedly decreases; iii) PrPc is efficiently secreted but not found associated to exocytosed vesicles and iv) PrPsc accumulation is completely inhibited. Against the ER-retained version of the same intrabody, expression of Sec-8H4 scFv does not influence maturation, glycosylation state and does not induce misfolding of endogenous PrPc. Instead, Sec8H4 scFv markedly alters the intracellular PrPc stability (3). The finding that both the ER-retained and the secretory version of the 8H4 intrabody block PrPsc formation by re-routing the intracellular traffic of prion and in different ways, indicates that the antiprion intrabodies are not only a valuable tool to study the pathogenetic mechanisms of prion diseases at molecular level but also an effective therapeutic strategy to inhibit scrapie infectivity.
1. Cardinale A, Filesi I, Vetrugno V, Pocchiari M, Sy MS and Biocca S (2005) J. Biol. Chem.; 7, 280:685-94. 2. Vetrugno V, Cardinale A, Filesi I, Mattei S, Sy MS, Pocchiari M and Biocca S (2005) BBRC; 338:1791-7. 3. Filesi I, Cardinale A, Mattei S and Biocca S (2007) J. Neurochem. In press
AD S. Biocca, I. Filesi, University of Tor Vergata, Dept. Neuroscience, Italy; A. Cardinale, IRCCS San Raffaele, Italy
SP englisch
PO Schottland