Role of Toll-like receptor-induced short non-coding RNAs in innate immune response

项目摘要和摘要 微生物感染会引起广泛的症状和疾病。持续努力了解 针对微生物感染的细胞防御机制是开发有效预防措施的关键 方法和治疗应用。先天免疫系统部署了各种模式识别受体， 包括Toll样受体(TLRs)，识别微生物的入侵并启动保护性反应。 TLRs在细胞表面或细胞内隔间(例如，内小体和溶酶体)以不同的方式表达 细胞类型，如巨噬细胞，并识别病原体相关分子模式(PAMP)，如 脂多糖(LPS)和肽聚糖(PGN)。PAMP识别启动信号转导 最终导致转录因子如NF-κB激活的途径，导致产生 保护宿主的细胞因子和趋化因子。在转录调控之后，TLR的下游 通路涉及多个水平的调控，包括转录后步骤。在这方面，简短的非- 编码RNA(NcRNAs)，包括那些来自转移RNA(TRNAs)的编码RNA(NcRNAs)已经进化为关键的POST。 转录调控因子。TRNA半部分构成了tRNA衍生的ncRNAs的一个主要亚群，并已被 被证明表达为与各种生物途径相关并与人类相关的功能RNA 神经退行性疾病和癌症等疾病。我们建议的研究的目标是阐明 TRNA先天积累相关半分子的表达谱及分子功能 免疫反应。我们最近发现，牛分枝杆菌卡介苗的感染上调了该基因的表达 人单核细胞来源的巨噬细胞(HMDM)中tRNA的一半。此外，tRNA的表达 HMDM中的一半通过表膜TLRs的激活而上调，从而使我们能够定义tRNA Halves作为一类新的TLR途径依赖的tRNA Hales。重要的是，tRNA的一半是丰富的 不仅在TLR途径激活的HMDM中蓄积，而且在其细胞外载体(EV)中蓄积，并具有 在激活内体TLR途径中的功能意义，提示这些tRNA的一半是 表达为促进免疫反应的功能分子。这些结果使我们假设 TRNA的一半可能是先天免疫反应中不可或缺的元素。我们建议全面确定 TLR途径诱导的tRNA在HMDM及其EVS中的表达谱(目标1) TLR途径如何诱导tRNA产生的生物发生机制(目标2)，以及 阐明tRNA半分子在内体TLR激活中的分子功能(目标3)。我们的研究将揭示 新的tRNA参与的ncRNA途径在先天性免疫反应中的作用，可能支持未来探索 针对tRNA半分子的微生物感染生物标志物和有效的治疗应用。

Project Summary and Abstract Infection of microbes causes a wide range of symptoms and diseases. Sustained efforts to understand the mechanism of cellular defense systems against microbe infections are essential to develop effective prevention methods and therapeutic applications. The innate immune system deploys various pattern-recognition receptors, including Toll-like receptors (TLRs), to recognize the invasion of microbes and initiate protective responses. TLRs are expressed at the cell surface or intracellular compartments (e.g., endosome and lysosome) in various cell types, such as macrophages, and recognize pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) and peptidoglycan (PGN). The PAMP recognition initiates signal transduction pathways that culminate in the activation of transcription factors such as NF-κB, resulting in production of cytokines and chemokines to protect the host. Following transcriptional regulation, the downstream of TLR pathways involves regulation at multiple levels including post-transcription steps. In this context, short non- coding RNAs (ncRNAs) including those derived from transfer RNAs (tRNAs) have evolved as key post- transcriptional regulators. tRNA halves constitute a major subgroup of tRNA-derived ncRNAs and have been shown to be expressed as functional RNAs associated with various biological pathways and linked to human diseases such as neurodegenerative diseases and cancers. The goal of our proposed studies is to elucidate the expression profile and molecular function of tRNA half molecules whose accumulation is involved in the innate immune response. We recently found that the infection of Mycobacterium bovis BCG upregulates the expression of tRNA halves in human monocyte-derived macrophages (HMDMs). Furthermore, the expression of tRNA halves in HMDMs is upregulated by the activation of surface membrane TLRs, allowing us to define the tRNA halves as a novel class of TLR pathway-dependent tRNA halves. Importantly, tRNA halves are abundantly accumulated not only in TLR pathway-activated HMDMs but also in their extracellular vehicles (EVs) and have functional significance in activation of endosomal TLR pathway, suggesting that those tRNA halves are expressed as functional molecules promoting immune response. These results have led us to hypothesize that tRNA halves can be integral elements in the innate immune response. We propose to comprehensively identify the expression profiles of TLR pathway-induced tRNA halves in HMDMs and their EVs (Aim 1), to investigate the biogenesis mechanism how the production of tRNA haves are induced by TLR pathways (Aim 2), and to elucidate the molecular function of tRNA halves in endosomal TLR activation (Aim 3). Our study will reveal a novel tRNA-engaged ncRNA pathway in the innate immune response and may support the future exploration of biomarkers and efficacious therapeutic applications targeting tRNA half molecules upon microbe infection.