Examining the role of TRMT1 and tRNA methylation in acute lung injury and ARDS

摘要： ARDS占重症监护病房(ICU)入院人数的十分之一。急性呼吸窘迫综合征的死亡率估计为30- 50%。数十年的临床试验未能确定显著影响的靶向药物疗法 病程。需要新的见解来扩大我们对潜在机制的理解 导致ARDS，促进新疗法的发展。 转移RNA(TRNA)占细胞总RNA含量的10%-20%。尽管古典上认为 被动翻译机制，最近的研究表明，tRNA可以在 对环境的反应。通过甲基化对tRNA进行翻译后修饰是一种机制，通过 哪些tRNA会对细胞压力做出反应。TRNA的甲基化可以改变翻译，改变区别 在“自我”和“非自我”之间，并保护tRNA免受碎片化。尽管如此，tRNAs在感染中的作用 而危重疾病是未知的。我们鉴定了一种名为TRMT1的甲基转移酶，它上调了 在人类肺部对感染作出反应。我们还发现，由TRMT1引起的tRNA甲基化在 对炎性刺激的反应。我们的初步数据表明，trmt1对巨噬细胞的活性至关重要。 和宿主在感染中的防御，以及维持细胞因子的反应。本应用程序重点介绍了 TRMT1在急性肺损伤中的作用及tRNA生物学研究--ARDS和危重患者的未知领域 护理疾病。 在这些研究的执行过程中，我们将检查髓系TRMT1是如何在 实验性肺损伤的免疫病理学研究。我们将确定TRMT1如何改变炎症信号和 在体外和体内调节细胞死亡。为了研究TRMT1的机械作用，我们将测量 TRNA甲基化对炎症刺激的反应和tRNA片段的产生。为了进一步 探索TRMT1的调控，我们将研究TRMT1的亚细胞转运是如何差异调控的 细胞质和线粒体tRNA甲基化及其如何改变炎症反应。最后， 因为TRMT1蛋白的细胞浓度可能在调节巨噬细胞行为和 我们将检测E3连接酶介导的TRMT1的泛素化和降解。 这些研究将首次阐明TRMT1在急性肺损伤中的作用。此外，这些研究 将为tRNA甲基化在肺损伤中的作用提供新的见解。这些研究的执行将提供 在急性肺损伤和ARDS领域的重大机制和生物学进展，并导致新的 治疗学的介入靶点。

Abstract: ARDS accounts for one in ten intensive care unit (ICU) admissions. Mortality in ARDS is estimated at 30 – 50%. Decades of clinical trials have failed to identify targeted pharmacotherapeutics that significantly impact disease course. New insights are needed to broaden our understanding of the underlying mechanisms that lead to ARDS to promote the development of novel therapeutics. Transfer RNA (tRNA) constitutes 10 – 20% of the total cellular RNA content. Although classically thought of passive translational machinery, more recent studies show that tRNA can be dynamically regulated in response to the environment. The post-translation modification of tRNA by methylation is one mechanism by which tRNAs respond to cellular stress. Methylation of tRNAs can alter translation, change the distinction between ‘self’ and ‘non-self’, and protect tRNAs from fragmentation. Despite this, the role of tRNAs in infection and critical illness is unknown. We identified a methyltransferase enzyme, termed TRMT1 that is upregulated in the human lung in response to infection. We also find that the methylation of tRNA by TRMT1 is altered in response to inflammatory stimuli. Our preliminary data suggest that the TRMT1 is vital for macrophage viability and host defense in infection, and for maintaining cytokine responses. This application focuses on the role of the TRMT1 in acute lung injury and the investigation of tRNA biology, unexplored territory in ARDS and critical care illnesses. During the execution of these studies, we will examine how myeloid TRMT1 contributes to immunopathology in experimental lung injury. We will determine how TRMT1 alters inflammatory signaling and regulates cell death in vitro and in vivo. To examine the mechanistic role of TRMT1, we will measure the methylation of tRNA in response to inflammatory stimuli and the production of tRNA fragments. To further explore the regulation of TRMT1, we will examine how subcellular trafficking of TRMT1 differentially regulates cytoplasmic and mitochondrial tRNA methylation and how this alters the inflammatory response. Finally, because cellular concentrations of TRMT1 protein may be crucial in regulating macrophage behavior and viability we will examine the E3 ligase mediated ubiquitination and degradation of TRMT1. These studies will be the first to elucidate the role of TRMT1 in acute lung injury. In addition, these studies will provide new insight into the role tRNA methylation in lung injury. The execution of these studies will provide significant mechanistic and biological advances in the field of acute lung injury and ARDS and lead to novel interventional targets for therapeutics.