Potent Antiscrapie Activities of Degenerate Phosphorothioate Oligonucleotides - Oligonucleotides

Potent Antiscrapie Activities of Degenerate Phosphorothioate Oligonucleotides
March 2006
David A. Kocisko,, Andrew Vaillant,, Kil Sun Lee,1 Kevin M. Arnold, Nadine Bertholet, Richard E. Race, Emily A. Olsen, Jean-Marc Juteau, and Byron Caughey
Antimicrobial Agents and Chemotherapy
Although transmissible spongiform encephalopathies (TSEs) are incurable, a key therapeutic approach is prevention of conversion of the normal, protease-sensitive form of prion protein (PrP-sen) to the disease-specific protease-resistant form of prion protein (PrP-res). Here degenerate phosphorothioate oligonucleotides (PS-ONs) are introduced as low-nM PrP-res conversion inhibitors with strong antiscrapie activities in vivo. Comparisons of various PS-ON analogs indicated that hydrophobicity and size were important, while base composition was only minimally influential. PS-ONs bound avidly to PrP-sen but could be displaced by sulfated glycan PrP-res inhibitors, indicating the presence of overlapping binding sites. Labeled PS-ONs also bound to PrP-sen on live cells and were internalized. This binding likely accounts for the antiscrapie activity. Prophylactic PS-ON treatments more than tripled scrapie survival periods in mice. Survival times also increased when PS-ONs were mixed with scrapie brain inoculum. With these antiscrapie activities and their much lower anticoagulant activities than that of pentosan polysulfate, degenerate PS-ONs are attractive new compounds for the treatment of TSEs.
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