Role of proinflammatory tRNA-derived RNAs in asthma

项目摘要和摘要 哮喘是一种慢性炎症性疾病，其特征是炎症、粘液产生、呼吸道 重塑和高反应性导致严重的支气管收缩。这些过程 涉及驻留的呼吸道细胞和浸润性炎症细胞之间的相互作用。变态反应性炎症 细胞因子、趋化因子和生长因子等介质作用于驻留的呼吸道细胞，包括 呼吸道平滑肌(ASM)导致结构和功能的改变。然而，知识差距 仍然是我们对炎症介质分子因素和机制的理解 调节ASM表型。炎性介质改变基因表达并促进 哮喘的发病机制。驻留呼吸道细胞基因表达的转录调控已被证实 经过广泛的研究。然而，靶细胞中的蛋白质功能可以在多个水平上进行调节 从转录开始，然后是转录后、翻译和翻译后步骤。在这方面， 包括来自转移RNA(TRNA)的小的非编码RNA(NcRNAs)已经进化 作为转录后基因表达的关键调节因子之一。 我们认为tRNA半分子是tRNA衍生的ncRNAs的一个主要亚类，在 哮喘的病理生理学，可作为哮喘的靶向治疗。在初步研究中，我们发现 小鼠肺表达特定的tRNA半种，其水平在 吸入室内粉尘(HDM)引起的过敏性炎症。此外，人类ASM 细胞表达tRNA的一半，其表达被促炎和 Th2型细胞因子、肿瘤坏死因子和白介素13。这些结果使我们能够 将tRNA半衰期定义为一类新的细胞因子依赖的tRNA半衰期，称为促炎 TRNA衍生的RNA(PIT-RNAs)。重要的是，siRNA引导的PIT-RNA的耗尽显著 损害ASM细胞的增殖，表明Pit-RNAs不仅仅是随着 TRNA的降解副产物，但表达为促进ASM细胞生长的功能性RNA。 这些结果使我们假设炎症介质在ASM中积累了Pit-RNAs 细胞，促进ASM的生长，在哮喘的分子发病机制中。我们建议 全面鉴定PIT-RNA表达谱(Aim 1)并研究其分子机制 Pit-RNA介导的ASM细胞功能的调节(Aim 2)，这将揭示一个新的tRNA参与 小RNA途径在哮喘发病机制中的作用及支持生物标志物和 针对tRNA减半的有效治疗应用。 。

Project Summary and Abstract Asthma is a chronic inflammatory disease characterized by inflammation, mucus production, airway remodeling, and hyper-responsiveness resulting in severe bronchoconstriction. These processes involve interplay among resident airway cells and infiltrated inflammatory cells. Allergic inflammatory mediators such as cytokines, chemokines, and growth factors act on resident airway cells including airway smooth muscle (ASM) resulting in structural and functional changes. However, knowledge gaps remain in our understanding of the molecular factors and mechanisms by which inflammatory mediators modulate ASM phenotype. Inflammatory mediators change gene expression and contribute to the pathogenesis of asthma. Transcriptional regulation of gene expression in resident airway cells has been studied extensively. However, protein function in a target cell can be regulated at multiple levels starting from transcription followed by post-transcription, translation and post-translation steps. In this context, small non-coding RNAs (ncRNAs) including the ones derived from transfer RNA (tRNA) have evolved as one of the key regulators of gene expression post-transcriptionally. We propose that tRNA halves, a major subgroup of tRNA-derived ncRNAs, play important roles in asthma pathobiology and can be targeted as asthma therapy. In preliminary studies, we found that mouse lung expresses specific tRNA half species whose levels are significantly upregulated during allergic inflammation caused by inhaled challenge of house dust mite (HDM). Furthermore, human ASM cells express tRNA halves and their expressions are promoted by treatments with pro-inflammatory and Th2 cytokines, tumor necrosis factor alpha (TNF) and interleukin 13 (IL-13). These results allow us to define the tRNA halves as a novel class of cytokine-dependent tRNA halves, termed proinflammatory tRNA-derived RNAs (pit-RNAs). Importantly, siRNA-directed depletion of pit-RNAs significantly impaired the proliferation of ASM cells, suggesting that pit-RNAs are not just accumulated as degradation by-products of tRNAs but are expressed as functional RNAs promoting ASM cell growth. These results have led us to hypothesize that inflammatory mediators accumulate pit-RNAs in ASM cells, which enhance ASM growth in the molecular pathogenesis of asthma. We propose to comprehensively identify pit-RNA expression profiles (Aim 1) and investigate molecular mechanisms of the pit-RNA-mediated modulation of ASM cell function (Aim 2), which will reveal a novel tRNA-engaged small RNA pathway in the pathogenesis of asthma and support the exploration of biomarkers and efficacious therapeutic applications targeting tRNA halves. .