Caprine PrP variants harboring Asp-146, His-154 and Gln-211 alleles display reduced convertibility upon interaction with pathogenic murine prion protein in scrapie infected cells

ABSTRACT

Scrapie, the prion disease of sheep and goats, is a devastating malady of small ruminants. Due to its infectious nature, epidemic outbreaks may occur in flocks/herds consisting of highly susceptible animals. Field studies identified scrapie-protective caprine PrP variants, harboring specific single amino acid changes (Met-142, Arg-143, Asp-146, Ser-146, His-154, Gln-211 and Lys-222). Their effects are under further evaluation, and aim to determine the most protective allele. We assessed some of these variants (Asp-146, His-154, Gln-211 and Lys-222), after their exogenous expression as murine-caprine chimeras in a scrapie- infected murine cell line. We report that exogenously expressed PrPs undergo conformational conversion upon interaction with the endogenous pathological murine prion protein (PrP^SC), which results in the detection of goat-specific and partially PK-resistant moieties. These moieties display a PK-resistance pattern distinct from the one detected in natural goat scrapie cases. Within this cellular model, distinct conformational conversion potentials were assigned to the tested variants. Molecules carrying the Asp-146, His-154 and Gln-211 alleles showed significantly lower conversion levels compared to wild type, confirming their protective effects against scrapie. Although we utilized a heterologous conversion system, this is to our knowledge, the first study of caprine PrP variants in a cellular context of scrapie, that confirms the protective effects of some of the studied alleles.

KEYWORDS:

• 22LN2a#58
• cell culture
• genotyping
• goats
• polymorphisms
• resistance
• Scrapie

DISCLOSURE OF POTENTIAL CONFLICTS OF INTEREST

No potential conflicts of interest were disclosed

ACKNOWLEDGMENTS

The authors would like to thank Dr. Sylvain Lehmann (Institute for Research in Biotherapy, INSERM, Montpellier, France) for providing the murine cell lines N2a58 and 22LN2a58; Dr. Christos Panagiotidis (School of Pharmacy, Aristotle University of Thessaloniki, Greece) for providing the pZeTa vector; Dr. Martin Groschup (Institute for Novel and Emerging Infectious Diseases, Friedrich-Loeffler Institut, Germany) for providing the L42 and P4 antibodies and Dr. Emmanuel Panteris (School of Biology, Aristotle University of Thessaloniki, Greece) for his valuable help on the acquisition of Confocal Laser Scanning Microscope images. We are grateful to Dr. Cynthia Humphreys Panagiotidis (School of Pharmacy, Aristotle University of Thessaloniki, Greece), for her valuable contribution to the experimental set-up and the final revision of the manuscript. This work is dedicated in memory of Captain Niko Lillios towards his endless trip to the lost Atlantis.

Funding

This research has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund. The study was supported by the EU project Goat-BSE (FOOD-CT-2006-36353).