Fernández-Borges Natalia, Parra Beatriz, Vidal Enric, Eraña Hasier, Sánchez-Martín Manuel A, de Castro Jorge, Elezgarai Saioa R, Pumarola Martí, Mayoral Tomás, Castilla Joaquín
CIC bioGUNE, Parque tecnológico de Bizkaia, Derio, Bizkaia, Spain.
Laboratorio Central de Veterinaria (LCV), Madrid, Spain.
PLoS Pathog. 2017 Nov 13;13(11):e1006716. doi: 10.1371/journal.ppat.1006716. eCollection 2017 Nov.
One of the characteristics of prions is their ability to infect some species but not others and prion resistant species have been of special interest because of their potential in deciphering the determinants for susceptibility. Previously, we developed different in vitro and in vivo models to assess the susceptibility of species that were erroneously considered resistant to prion infection, such as members of the Leporidae and Equidae families. Here we undertake in vitro and in vivo approaches to understand the unresolved low prion susceptibility of canids. Studies based on the amino acid sequence of the canine prion protein (PrP), together with a structural analysis in silico, identified unique key amino acids whose characteristics could orchestrate its high resistance to prion disease. Cell- and brain-based PMCA studies were performed highlighting the relevance of the D163 amino acid in proneness to protein misfolding. This was also investigated by the generation of a novel transgenic mouse model carrying this substitution and these mice showed complete resistance to disease despite intracerebral challenge with three different mouse prion strains (RML, 22L and 301C) known to cause disease in wild-type mice. These findings suggest that dog D163 amino acid is primarily, if not totally, responsible for the prion resistance of canids.
朊病毒的特征之一是它们能够感染某些物种而不能感染其他物种，抗朊病毒的物种因其在破译易感性决定因素方面的潜力而备受关注。此前，我们开发了不同的体外和体内模型，以评估那些被错误地认为对朊病毒感染具有抗性的物种的易感性，比如兔科和马科的成员。在这里，我们采用体外和体内方法来了解犬科动物尚未解决的低朊病毒易感性问题。基于犬朊病毒蛋白（PrP）氨基酸序列的研究，以及计算机模拟结构分析，确定了独特的关键氨基酸，其特性可能使其对朊病毒疾病具有高度抗性。进行了基于细胞和大脑的蛋白质错误折叠循环扩增（PMCA）研究，突出了D163氨基酸在蛋白质错误折叠倾向中的相关性。通过构建携带这种替代的新型转基因小鼠模型也对此进行了研究，尽管用三种已知能在野生型小鼠中引发疾病的不同小鼠朊病毒株（RML、22L和301C）进行脑内攻击，这些小鼠仍表现出对疾病的完全抗性。这些发现表明，犬科动物的D163氨基酸即使不是完全负责，也是主要负责犬科动物对朊病毒的抗性。
