Immune-modulating nucleotide modifications within tRNA

tRNA 内的免疫调节核苷酸修饰

• 批准号: 244255133
• 负责人: Professor Dr. Alexander Dalpke
• 金额: --
• 依托单位: Abteilung Medizinische Mikrobiologie und Hygiene
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/244255133?language=en
• 关键词: Immune; modulating; nucleotide; modifications; within

The innate immune system recognizes conserved, microbial structures including nucleic acids by pattern recognition receptors. Recognition of foreign, microbial nucleic acids is based on differences in sequences and structure, presence of nucleotide modifications and subcellular compartmentalization of the respective receptors. As recognition of foreign RNA results in induction of an immune response, it is of interest to examine and define structural requirements for the recognition of microbial nucleic acids. The results will impact basic research as well as application of therapeutic RNAs. So far, experiments addressing the role of nucleotide modifications have mainly been done using synthetic oligoribonucleotides whereas the importance of sequence, structure and modifications within natural RNA has not been studied intensively.The applicants could show recently, that Toll-like receptor 7 (TLR7) not only recognizes single-stranded RNA but is also activated by bacterial tRNA. The decisive discrimination of bacterial versus host tRNA was due to the presence of various, naturally occurring nucleotide modifications, among which the applicants identified an inhibitory 2'-O-methylation at guanosine 18 (Gm18).The new results on inhibitory modifications within the natural tRNA context were obtained by combining techniques in RNA synthesis and analysis with immunobiological assays. The newly developed techniques are now to be used to answer basic questions of RNA recognition by TLR7. It is intended to identify the molecular mechanism by which Gm18 suppresses an immune response. Therefore, positional effects and cellular signal transduction will be analyzed. Furthermore, new immune-modulating nucleotide modifications will be identified within bacterial and eukaryotic RNA using LC/MS and the recently developed synthesis of chimeric (modified and unmodified) RNAs. Finally, functions of the identified nucleotide modifications with respect to foreign/self discrimination and a potential role for bacterial immune evasion will be studied.The experiments are expected to gain insight into the less well examined topic of immune-modulation by RNA nucleotide modifications. Of note, the experiments will be done within the context of natural RNA. Inhibitory modifications might be of use for the targeted manipulation of innate immunity.

先天免疫系统通过模式识别受体识别保守的微生物结构，包括核酸。外来微生物核酸的识别是基于序列和结构的差异、核苷酸修饰的存在和相应受体的亚细胞区室化。由于外源RNA的识别导致免疫应答的诱导，因此感兴趣的是检查和定义识别微生物核酸的结构要求。这些结果将影响基础研究以及治疗性RNA的应用。迄今为止，解决核苷酸修饰的作用的实验主要是使用合成的寡核糖核苷酸完成的，而天然RNA中序列、结构和修饰的重要性尚未被深入研究。申请人最近可以表明，Toll样受体7（TLR 7）不仅识别单链RNA，而且还被细菌tRNA激活。细菌与宿主tRNA的决定性区别是由于存在各种天然存在的核苷酸修饰，其中申请人鉴定了鸟苷18（Gm 18）处的抑制性2 '-O-甲基化。通过将RNA合成和分析技术与免疫生物学测定相结合，获得了天然tRNA背景下抑制性修饰的新结果。新开发的技术现在被用来回答TLR 7识别RNA的基本问题。其目的是确定Gm 18抑制免疫应答的分子机制。因此，位置效应和细胞信号转导将被分析。此外，新的免疫调节核苷酸修饰将使用LC/MS和最近开发的嵌合（修饰和未修饰）RNA的合成在细菌和真核RNA内鉴定。最后，功能的识别核苷酸修饰相对于外来/自我歧视和细菌免疫evasions.The实验的潜在作用将有望深入了解不太好的审查主题的免疫调节RNA核苷酸修饰。值得注意的是，实验将在天然RNA的背景下进行。抑制性修饰可能用于先天免疫的靶向操纵。