NR AXSU
AU Mohorko,N.; Makarava,N.; Baskakov,I.V.; Petric,A.; Kepe,V.; Barrio,J.R.; Bresjanac,M.
TI FDDNP Labelling of Prion Amyloid Fibrils in Vitro
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.75
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
As presented in previous Prion meetings, a fluorescent probe FDDNP, whose 18Flabelled analogue has been used to detect ß-amyloid plaques and neurofibrillary tangles in Alzheimer disease patients1, labells prion plaques in vitro2,3. [18F]FDDNP PET scan has recently been used in Indiana kindred Gerstmann-Strausler-Scheinker (GSS) disease patients and presymptomatic subjects to view brain prion pathology in vivo4. In these studies, FDDNP has shown considerable potential for diagnostic use. However, ahead of use of FDDNP in clinical diagnosis, detailed biochemical studies of FDDNP interaction with prion protein are needed.
In the present study, TEM-verified hamster and mouse full-length recombinant prion protein (rPrP) fibrils of highly purified rPrP5 were used in fluorescence FDDNP titration experiments, where FDDNP behaviour was compared to Thioflavin T (ThT). In a similar model, submicromolar range for Kd of FDDNP in recombinant human truncated PrP
(rhPrP) aggregates had been determined3. Binding of FDDNP to fibrils was further characterized under fluorescent microscope. Radioassays of [18F]FDDNP binding to full-length rPrP fibrils are planned.
FDDNP was found to bind to full-length rPrP fibrils avidly and comparably to ThT. FDDNP labelled fibril morphology can be studied under fluorescent microscope. Based on tissue labelling and earlier fluorimetric determination of FDDNP Kd on
truncated rhPrP aggregates3, we expect to obtain binding constants of [18F]FDDNP to full-length mouse and hamster rPrP fibrils similar to the binding constants of [18F]FDDNP to ß-amyloid fibrils6.
These results may offer the basis for further development of FDDNP as a diagnostic tool in prion diseases.
1 Shoghi-Jadid et al, Am J Geriatr Psychiatry. 2002 Jan-Feb;10(1):24-35.
2 Bresjanac et al, J Neurosci. 2003 Sep 3;23(22):8029-33.
3 Hafner Bratkovic et al, Prion 2005, Düsseldorf; poster.
4 Ghetti et al, Prion 2006, Turin; poster.
5 Bocharova et al, J Mol Biol. 2005 Feb 18;346(2):645-59.
6 Agdeppa et al, J Neurosci. 2001 Dec 15;21(24):RC189.
AD N. Mohorko, M. Bresjanac, Medical Faculty, University of Ljubljana, Slovenia; N. Makarava, I.V. Baskakov, University of Maryland Biotechnology Institute, USA; A. Petric, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia; V. Kepe, J.R. Barrio, David Geffen School of Medicine at UCLA, USA
SP englisch
PO Schottland