NR APAI
AU Weiss,S.
TI The role of the 37kDa/67 kDAa laminin receptor in the life cycle of prions
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Oral sessions OS-11
PT Konferenz-Vortrag
AB
We have identified the 37 kDa 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) acts as the cell surface receptor for PrPc (2). HSPGs have been identified as co-factors/co-receptors for the PrP-LRP/LR binding reaction (3) and heparan sulfate binding sites in the cellular prion protein have been identified (4).
Very recently, we demonstrated that LRP/LR is required for PrPsc propagation in neuronal cells (5). Here, we abolished PrPsc propagation in cultured cells by three approaches, all targeting the 37 kDa/67 kDa LRP/LR: (i) Transfection of a construct expressing antisense LRP RNA, (ii) transfection of small interfering (si)RNAs directed against the LRP mRNA and (iii) incubation of ScN2a cells with the polyclonal anti-LRP antibody W3. All three approaches resulted in cessation of PrPsc propagation in scrapie propagating neuronal cells. The treatments also reduced the PrPc level to approx. 50%. Cells remained free of PrPsc after being cultured for 14 additional days without the LRP/LR specific antibody, whereas PrPc levels were totally restored (5).
Employing the Semliki-Forest-Virus (SFV) system, we investigated binding and internalization of the proteinase K-digested mouse scrapie prion protein moPrP27-30 on mammalian cells. Binding of moPrP27-30 to BHK cells was enhanced when LRP::FLAG was overexpressed to the cell surface and LRP/LR specific antibodies totally blocked the binding reaction suggesting that the 37 kDa/67 kDa laminin receptor acts as the receptor for the infectious scrapie prion protein. Expression of recombinant mouse PrP to the cell surface increased the binding of moPrP27-30 suggesting that the cellular prion protein might contribute to the cell binding of the infectious isoform. Internalization studies employing protease protection assays suggest that moPrP27-30 becomes internalized LRP/LR dependently.
The polyanion pentosan polysulfate (SP 45) has a prophylactic potential in TSEs and was found to protect VM and CBA mouse strains totally from ME7 prions (6). Here we show that the binding of moPrP27-30 to LRP::FLAG overexpressing BHK cells can be reduced by pre-incubation with 100 µg/ml of pentosan polysulfate. This suggests that the substance might interfere with scrapie prion propagation due to its blocking capacity of the moPrP27-30-37kDa/67kDa LRP/LR interaction on the cell surface.
1. Rieger, R., Edenhofer, F., Lasmezas, C.I. and Weiss, S. (1997) Nat Med, 3, 1383-8.
2. Gauczynski, S., Peyrin, M., Haïk, S., Leucht, C., Hundt, C., Rieger, R., Krasemann, S., Deslys,
J.-P., Dormont, D., Lasmézas, C.I. and Weiss, S. (2001) EMBO J, 20, 5863-5875.
3. Hundt, C., Peyrin, J.-M., Haïk, S., Gauczynski, S., Leucht, C., Riley, M.-L., Rieger, R., Deslys,
J.-P., Dormont, D., Lasmézas, C.I. and Weiss, S. (2001) EMBO J, 20, 5876-5886.
4. Warner, R.G., Hundt, C., Weiss, S. and Turnbull, J.E. (2002) J. Biol. Chem. 277, 18421-18430.
5. Leucht, C., Simoneau, S., Rey, C., Vana, K., Rieger, R., Lasmezas, C. I., and Weiss, S. (2003) EMBO Rep 4, 290-295.
6. Farquhar, C., Dickinson, A. and Bruce, M. (1999) Lancet, 353, 117.
AD Stefan Weiss, LMU University of Munich, Germany
SP englisch
PO Deutschland