Extracellular miRNAs, innate immunity, and critical illness

项目摘要 脓毒症和缺血性心肌梗死是两种死亡率很高的危重疾病。而他们的 病因是明显不同的，它们具有先天免疫激活，标记组织 炎症和急性心功能障碍。组织炎症，主要由先天免疫激活驱动， 是脓毒症和心肌缺血-再灌注（I/R）中心脏损伤的主要决定因素。我们发现 宿主细胞RNA和各种miRNA在鼠/人脓毒症和心肌缺血期间释放到血液中。 I/R。循环宿主RNA与脓毒症严重程度密切相关，并参与心肌I/R损伤， 动物RNAseq揭示了miRNA是健康人和糖尿病患者血浆RNA的主要生物型（70%）。 败血症小鼠和人类。此外，我们已经报道，这些细胞外（前）-RNA和某些尿苷丰富的 ex-miRNAs作为损伤相关分子模式（DAMP）发挥作用并驱动先天免疫应答 通过TLR 7依赖的途径。利用计算机算法，我们已经确定了两个miRNA序列， 基序被证明是必不可少的miRNA诱导的先天免疫激活。最后，TLR 7基因缺失 减弱细胞因子风暴/凝血病并提高脓毒症动物的存活率。本研究的目的 该项目旨在描述ex-miRNAs在先天免疫激活和免疫应答中的功能和机制。 脓毒症的发病机制和心肌I/R损伤。具体而言，我们将解决以下三个关键问题：1） ex-miRNAs在脓毒症的系统性先天免疫激活和心功能障碍中的作用， 在I/R后心肌炎症和梗死中的作用2)什么是潜在的机制负责 在败血症和心肌I/R期间，ex-miRNA介导的心脏损伤和功能障碍？3)我们能开发一个 抗-miRNA或抗-TLR 7策略以减弱脓毒症诱导的心肌病并改善存活率， 减少I/R后心肌损伤？我们将使用小鼠模型和败血症的生物标本/临床数据， 患者这项工作代表了miRNA生物学的一个范式转变--它作为DAMP的独特功能， 先天免疫和两种由先天免疫驱动的炎症主导的严重疾病。

Project Summary Sepsis and ischemic myocardial infarction (MI) are two critical illnesses with very high mortality. While their etiologies are distinctively different, they share similar features of innate immune activation, marked tissue inflammation, and acute cardiac dysfunction. Tissue inflammation, largely driven by innate immunity activation, is a major determinant of cardiac injury in sepsis and myocardial ischemia-reperfusion (I/R). We have found that host cellular RNA and various miRNAs are released into the blood during murine/human sepsis and myocardial I/R. Circulating host RNA is closely correlated with sepsis severity and contributes to myocardial I/R injury in animals. RNAseq reveals that miRNAs are the dominant biotype (70%) of plasma RNAs in both healthy and septic mice and human. Moreover, we have reported that these extracellular (ex)-RNAs and certain uridine-rich ex-miRNAs function as a damage-associated molecular pattern (DAMP) and drive innate immune response through a TLR7-dependent pathway. Using a computer algorithm, we have identified two miRNA sequence motifs proven to be essential for miRNA-induced innate immunity activation. Finally, genetic deletion of TLR7 attenuates cytokine storm/coagulopathy and improves survival in sepsis animals. The goal of this research program is to delineate the function and mechanism of ex-miRNAs in innate immunity activation and in the pathogenesis of sepsis and myocardial I/R injury. Specifically, we will address the following 3 key questions: 1) What are the roles of ex-miRNAs in systemic innate immunity activation and cardiac dysfunction in sepsis, and in myocardial inflammation and infarction following I/R? 2) What are the underlying mechanisms responsible for ex-miRNA-mediated cardiac injury and dysfunction during sepsis and myocardial I/R? 3) Can we develop an anti-miRNA or anti-TLR7 strategy to attenuate sepsis-induced cardiomyopathy and improve survival, and to reduce myocardial injury after I/R? We will use both mouse models and biospecimens/clinical data of septic patients. The proposed work represents a paradigm shift in miRNA biology – its unique function as a DAMP in innate immunity and in two critical illnesses that are dominated by innate immunity-driven inflammation.