Emergence of drug resistance in prion populations

朊病毒群体中出现耐药性

• 批准号: 8459525
• 负责人: ROY G SMITH
• 金额: $ 40.96万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8459525
• 关键词: Amino Acid Sequence; Bacteria; Biological Assay; Brain; Cell Culture Techniques; Cell Line; Cells; Characteristics; Chemicals; Chronic; Complex; Cultured Cells; Discrimination; Drug resistance; Drug-sensitive; Environment; Exhibits; Genetic Materials; Heterogeneity; Hydrochloride Salt; Infection; Investigation; Isomerism; Laboratories; Molecular Conformation; Mus; Mutation; Neuroblastoma; Nucleic Acids; Pharmaceutical Preparations; Population; PrPC Proteins; PrPSc Proteins; Prion Diseases; Prions; Process; Property; Proteins; RNA Phages; RNA Viruses; Relative (related person); Resistance; Resistance development; Scrapie; Temperature; Therapeutic; Time; Variant; Virus; Work; abstracting; base; brain cell; conformer; design; glycosylation; guanidinium; inhibitor/antagonist; innovation; mutant; pathogen; prevent; protein misfolding cyclic amplification; research study; treatment strategy

Abstract Prions, the pathogens causing transmissible spongiform encephalopathies, are unique in that they consist mainly, if not entirely of multimers of PrPSc, a conformational isomer of the host- encoded protein PrPC. Prions occur in the form of diverse strains, which differ in various phenotypic properties but whose PrPSc has the same amino acid sequence. It is believed that strain identity is encoded by the conformation of PrPSc and that there are as many distinct conformations as there are strains. We have observed that a prion strain, 22L, when transferred from brain to cell culture, changed its characteristics, but gradually regained them when re-introduced into brain. Moreover, when propagated in cell culture in the presence of an inhibitory drug, swainsonine, the prion population acquired resistance against the drug, but lost the resistance when propagated for prolonged periods in its absence. This is quite remarkable, considering that bacteria and viruses acquire drug resistance as a consequence of random mutations in their genetic material, whereas prions do not contain informational nucleic acids. Our working hypothesis is that a prion strain population is comprised not of PrPSc with a unique conformation but of a multitude of species ("sub-strains") with related conformations. This is analogous to the concept of "quasispecies" we first established for RNA phages three decades ago. We postulate that the replication rates of sub-strains may vary depending on the host cell. In a particular environment one of these species may represent the major component and out- replicate other conformers, but at the same time, variant conformers are continuously generated at some low rate (because the activation energy barriers for interconversion are low). Upon transfer to a different host or a change in the environment a different conformer may become the major constituent of the population. We wish to determine whether PrPSc associated with drug resistant and drug sensitive prions show physico-chemical differences that may reflect different conformations, and whether the two types of prions replicate at different rates in host cells. We will investigate whether prions can develop resistance against other inhibitory drugs. Importantly, we will determine whether prion populations that have never been exposed to swainsonine already comprise resistant variants, as would be expected from the "quasispecies" hypothesis. We intend to biologically clone a drug-sensitive prion and determine whether swainsonine-resistant variants arise during propagation in the absence of the drug, and if so, at what rate. Finally, we will ascertain whether it is possible to select prion "sub-strains" that are more resistant to chaotropic agents or to temperature, which would be further evidence in favor of heterogeneity of prion populations. The major technical innovation making this investigation possible is the Cell Panel Assay (CPA), which is based on the Standard Scrapie Cell Assay (SSCA), both of which were developed in our laboratories and which allow the rapid discrimination between prion strains. The finding that prions can acquire drug resistance impacts on the strategies envisaged for therapeutic approaches to prion disease.

抽象的 prions，导致可传染的海绵状脑病的病原体是独一无二的 它们主要组成，即使不是完全由PRPSC的多聚体组成，宿主的构象异构体 - 编码的蛋白质PRPC。王室以各种菌株的形式出现，各种不同 表型特性，但其PRPSC具有相同的氨基酸序列。相信 应变身份是通过PRPSC的构象来编码的，并且存在尽可能多的不同 构象有菌株。 我们已经观察到，当从大脑转移到细胞培养的prion菌株22L改变了它的变化 特征，但在重新引入大脑时会逐渐恢复它们。而且，什么时候 在存在抑制性药物瑞士氨酸的情况下，在细胞培养中传播 获得了对该药物的抵抗，但在延长的繁殖时失去了抵抗力 在不在的情况下。考虑到细菌和病毒获取，这是非常了不起的 由于其遗传物质中随机突变而导致的耐药性，而王室 不含信息核酸。 我们的工作假设是，prion菌株人群不包括具有独特的PRPSC 构象，但具有相关构象的多种物种（“亚菌”）。这是 类似于我们最初为RNA噬菌体建立的“准特质”的概念三十年 前。我们假设亚构件的复制速率可能会根据宿主细胞而变化。在 这些物种的特定环境可能代表主要组成部分，并且 复制其他构型，但与此同时，变体构象异构体是连续生成的 以某种较低的速度（因为互转换的激活能屏障很低）。之上 转移到其他主机或环境中的变化可能会变成不同的构象异构体 人口的主要组成部分。 我们希望确定PRPSC是否与耐药性和药物敏感prions相关 显示出可能反映不同构象的物理化学差异，以及是否是否 两种类型的prions在宿主细胞中以不同的速率复制。我们将调查王子是否 可以对其他抑制性药物产生抗性。重要的是，我们将确定是否 从未暴露于瑞士宁氨酸已经包含抗性的prion人群 正如“准人”假设所期望的那样。我们打算在生物学上 克隆对药物敏感的prion，并确定在 在没有药物的情况下繁殖，如果是的，则以什么速度的繁殖。最后，我们将确定是否 可以选择对Chaotropic剂或对 温度，这将是有利于王室种群异质性的进一步证据。 使这项研究成为可能的主要技术创新是细胞面板测定（CPA）， 这是基于标准的crapie细胞测定法（SSCA），这两者都是在 我们的实验室，允许prion菌菌株之间的快速歧视。 prion王可以获得耐药性影响的发现对所设想的策略的影响 治疗方法的治疗方法。

项目成果

Mutability of prions.

• DOI: 10.1038/embor.2011.191
• 发表时间: 2011-12-01
• 期刊: EMBO REPORTS
• 影响因子: 7.7
• 作者: Li, Jiali;Mahal, Sukhvir P.;Mahal, P.;Demczyk, Cheryl A.;Weissmann, Charles
• 通讯作者: Weissmann, Charles

Propagation of RML prions in mice expressing PrP devoid of GPI anchor leads to formation of a novel, stable prion strain.

• DOI: 10.1371/journal.ppat.1002746
• 发表时间: 2012
• 期刊: PLoS pathogens
• 影响因子: 6.7
• 作者: Mahal SP;Jablonski J;Suponitsky-Kroyter I;Oelschlegel AM;Herva ME;Oldstone M;Weissmann C
• 通讯作者: Weissmann C