Mechanism of cytotoxicity of ricin

蓖麻毒素的细胞毒性机制

• 批准号: 7630083
• 负责人: NILGUN E TUMER
• 金额: $ 3.64万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-15 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7630083
• 关键词: Address; Adenine; Aerosols; Antidotes; Apoptosis; Apoptotic; Binding; Biochemical; Biological Models; Biological Warfare; Bioterrorism; Breathing; Categories; Cell Death; Cells; Cessation of life; Cytosol; Defect; Depurination; Development; Endocytosis; Endoplasmic Reticulum; Enterotoxins; Genes; Genome; Genomics; Induction of Apoptosis; Intoxication; Lectin; Lung; MAPK14 gene; MAPK8 gene; Mammalian Cell; Measures; Medical; Membrane; Messenger RNA; Molecular; Mutagenesis; N glycosidase; National Institute of Allergy and Infectious Disease; Plants; Plasmids; Process; Protein Biosynthesis; Protein Synthesis Inhibition; Proteins; RNA Splicing; Resistance; Respiratory System; Ribosomal RNA; Ribosomes; Ricin; Ricinus communis; Risk; Role; Signal Pathway; Signal Transduction; Small Interfering RNA; System; Techniques; Terrorism; Toxin; Translations; Vaccines; Yeasts; base; biodefense; cell injury; cell killing; cytotoxicity; design; instrument; mutant; novel therapeutics; prevent; prototype; response; ribosomal A-protein

Ribosome inactivating proteins (RIPs) have been used as instruments of biological warfare and terrorism. Ricin is a heterodimeric plant toxin that consists of A and B-chains and the prototype of type II RIPs. Its B- chain is a lectin that enables cell binding. After endocytosis, the A-chain translocates through the endoplasmic reticulum membrane to reach the cytosol where its N-glycosidase activity removes a specific adenine from the highly conserved, sarcin/ricin loop (SRL) in the large rRNA. Ricin has been classified as Category B priority for biodefense. Very little is known about the membrane translocation and ribosome interactions of ricin and the molecular mechanism by which it causes apoptosis in mammalian cells. We have established yeast as a biologically relevant model system to study the activity of RTA, and isolated mutant forms of RTA, which do not kill cells. Translation inhibition by ribosome depurination has been hypothesized to be responsible for the cytotoxicity of ricin. However, our preliminary analysis of the nontoxic RTA mutants indicates that ribosome depurination is necessary, but not sufficient for cytotoxicity. We further showed that wild type RTA inhibits induction of the unfolded protein response (UPR) in yeast and in mammalian cells and induces activation of JNK, p38 and ERK signaling pathways in mammalian cells. This project aims to use yeast and mammalian cells as complementary systems to understand the molecular basis for ricin intoxication. Specific Aims: 1. Using the nontoxic RTA mutants, determine if ribosome binding and depurination are required for cytotoxicity in yeast and induction of apoptosis in mammalian cells. 2. Characterize the interaction between RTA and ribosomal protein POand determine if binding to POis essential for ribosome depurination by RTA. 3. Determine if RTA causes cell death by inhibiting the development of UPR in yeast and in mammalian cells. 4. Identify the cellular genes necessary for cytotoxicity of RTA in yeast. Ricin is not only a bioterrorism threat, but inhibits translation by a similar mechanism as the bacterial enterotoxins. Therefore, the studies outlined in this application will have important implications for the design of protection strategies against AB-toxins that are classified as high-risk candidates for bioterrorism.

核糖体灭活蛋白（RIP）已被用作生物战和恐怖主义的工具。 Ricin是一种异二聚体植物毒素，由A和B链和II型撕裂的原型组成。它的b- 链是一种可实现细胞结合的凝集素。内吞作用后，A链通过 内质网膜到达其N-糖苷酶活性去除特定的细胞质 大rRNA中的高度保守的萨尔辛/ricin环（SRL）的腺嘌呤。赖辛已被归类为 B BiodeFense的B类优先级。关于膜易位和核糖体知之甚少 ricin和它引起哺乳动物细胞凋亡的分子机制的相互作用。我们 已经建立了酵母作为生物学相关的模型系统，以研究RTA的活性并孤立 RTA的突变形式，不会杀死细胞。核糖体删除的翻译抑制作用已是 假设负责ricin的细胞毒性。但是，我们对无毒的初步分析 RTA突变体表明核糖体脱育是必要的，但不足以使细胞毒性。我们进一步 表明野生型RTA抑制了酵母和在 哺乳动物细胞并诱导哺乳动物细胞中JNK，p38和ERK信号通路的激活。这 项目旨在将酵母和哺乳动物细胞用作互补系统来了解分子 赖以蛋白中毒的基础。具体目的：1。使用无毒的RTA突变体，确定核糖体是否 酵母中细胞毒性和诱导哺乳动物细胞的凋亡是必需的。 2。表征RTA和核糖体蛋白po的相互作用确定是否与POI结合 RTA的核糖体脱育至关重要。 3。确定RTA是否通过抑制 UPR在酵母和哺乳动物细胞中的发展。 4。确定细胞基因 酵母中RTA的细胞毒性。 ricin不仅是生物恐怖主义威胁，而且抑制了类似的翻译 机理作为细菌肠毒素。因此，本申请中概述的研究将有 对针对AB毒素的保护策略的设计的重要意义，该策略被归类为高风险 生物恐怖主义的候选人。