NR ARDD
AU Weiss,S.
TI The 37 kDa/67 kDa Laminin Receptor as a Target in Therapy of Prion Diseases
QU TSE-Forum, 4. Kongress - Nationale TSE-Forschungsplattform, Düsseldorf 28.10.-29.10.2004, Vortrag V-20
PT Konferenz-Vortrag
AB
We identified the 37kDa laminin receptor precursor (LRP) as an interactor for the cellular prion protein (PrPc) (1) and proved that the 37 kDa/67 kDa laminin receptor (LRP/LR) (2) and HSPGs (3,4) act as the cell surface receptor and co-receptors for PrPc, respectively.
The laminin receptor is required for propagation of the Scrapie form of the prion protein PrPsc (5). Knock-down of the 37 kDa/67 kDa laminin receptor in mouse brain by ectopic expression of antisense LRP RNA resulted in a significant reduction of LRP/LR levels in the cerebellum and the hippocampus (6). These mice have been inoculated with PrPsc and their incubation time might be prolonged compared to wild-type mice.
Data from the Semliki-Forest Virus (SFV) system suggest that the laminin receptor also acts as the receptor for PrPsc wheras PrPc might act as a co-receptor for PrPsc. Pentosan Polysulfate (SP 45) and the heparan sulfate mimetic HM2602 significantly reduce moPrP27-30 cell binding. These sulfated glycans, especially HM2602 might act as powerful therapeutics in treatment of TSEs.
Live cell imaging with moLRP-DsRed and EGFP-moPrP revealed that moLRP-DsRed migrates with approx. 70 nm/sec and EGFP-moPrP with approx. 50 nm/sec. Co-transfection studies employing fluorochrome-labeled cell compartment specific marker proteins, prion and receptor molecules will identify the subcellular distribution of PrP and LRP/LR.
The prion-like protein Doppel (Dpl) fails to interact with itself, the laminin receptor and the prion protein in a yeast two hybrid analysis, suggesting that Dpl and PrP are not or only marginally related regarding their ligand binding behaviour (7).
Single chain antibodies (scFvs) directed against the 37 kDa/67 kDa laminin receptor have been selected from naïve and synthetic scFv libraries and recognize specifically LRP/LR. Anti-LRP/LR scFvs will be delivered to animals by i.c. injection of rec. Adeno-associated viruses (AAV), grafting of scFv secreting muscle cells and i.p. injection of scFvs.
SiRNAs directed against LRP mRNA prohibit PrPsc propagation in cultured cells (5).
We constructed rec. lentiviruses expressing siRNAs directed against LRP mRNA and applied these viruses to neuronal cells. Rec. lentiviruses will be delivered to scrapie infected mice and possibly prolonged incubation times will be monitored.
scFvs directed against LRP/LR, siRNAs directed against LRP mRNA and the HM2602 interfering with PrPsc cell binding represent alternative tools in therapy of prion diseases.
(1) Rieger et al. (1997) Nat. Med. 3, 1383-1388. (2) Gauczynski et al. (2001) EMBO J. 20, 5863-5875. (3) Hundt et al. (2001) EMBO J. 20, 5876-5886. (4) Warner et al. (2002) J. Biol. Chem. 277, 18421-18430. (5) Leucht et al. (2003) EMBO rep 4, 290-295. (6) Leucht et al. (2004) Transgenic Res 13, 81-85. (7) Hundt & Weiss (2004) Biochim. Biophys. Acta 1689, 1-5.
AD Stefan Weiss - Genzentrum - Institut für Biochemie der LMU München, Feodor-Lynen-Str.25, D-81377 München, Germany
SP englisch
PO Deutschland
OR Tagungsband