Destabilizing polymorphism in cervid prion protein hydrophobic core determines prion conformation and conversion efficiency

PLoS Pathogens

Sabine Gilch¹  Holger Wille¹  Sara Amidian¹  Lyudmyla Dorosh¹  Yo Ching Cheng²  Samia Hannaoui³  Camilo Duque Velásquez³  Glenn Telling³  Debbie McKenzie⁴  Sampson Law⁴  Maria Stepanova⁵ 

[1] Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada;Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada;Department of Ecosystem and Public Health, Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada;Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada;Prion Research Center, Colorado State University, Fort Collins, Colorado, United States of America

关键词: Animal prion diseases;    Chronic wasting disease;    Deer;    Biochemical simulations;    Molecular dynamics;    Prion diseases;    Mouse models;    Prisms;   

DOI  :  10.1371/journal.ppat.1006553

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Prion diseases are infectious neurodegenerative disorders of humans and animals caused by misfolded forms of the cellular prion protein PrPC. Prions cause disease by converting PrPC into aggregation-prone PrPSc. Chronic wasting disease (CWD) is the most contagious prion disease with substantial lateral transmission, affecting free-ranging and farmed cervids. Although the PrP primary structure is highly conserved among cervids, the disease phenotype can be modulated by species-specific polymorphisms in the prion protein gene. How the resulting amino-acid substitutions impact PrPC and PrPSc structure and propagation is poorly understood. We investigated the effects of the cervid 116A>G substitution, located in the most conserved PrP domain, on PrPC structure and conversion and on 116AG-prion conformation and infectivity. Molecular dynamics simulations revealed structural de-stabilization of 116G-PrP, which enhanced its in vitro conversion efficiency when used as recombinant PrP substrate in real-time quaking-induced conversion (RT-QuIC). We demonstrate that 116AG-prions are conformationally less stable, show lower activity as a seed in RT-QuIC and exhibit reduced infectivity in vitro and in vivo. Infectivity of 116AG-prions was significantly enhanced upon secondary passage in mice, yet conformational features were retained. These findings indicate that structurally de-stabilized PrPC is readily convertible by cervid prions of different genetic background and results in a prion conformation adaptable to cervid wild-type PrP. Conformation is an important criterion when assessing transmission barrier, and conformational variants can target a different host range. Therefore, a thorough analysis of CWD isolates and re-assessment of species-barriers is important in order to fully exclude a zoonotic potential of CWD.

【 授权许可】

CC BY