Mechanistic insights into the systemic inflammation and organ failure in sepsis

描述（由申请方提供）：脓毒症是一种严重疾病，是危重患者的主要死亡原因。其特征在于全身炎症反应综合征（SIRS）及其相关的多器官衰竭（MOF）。脓毒症相关SIRS/MOF的发病机制仍然知之甚少，治疗/诊断选择仍然有限。SIRS/MOF发展的剩余问题之一是局灶性感染如何被夸大为全身性炎症。基于我们已发表的和初步的研究，我们认为外泌体穿梭miRNAs在将炎症信号传递到远处的靶细胞和器官中起着至关重要的作用。miR-15 a和miR-16紧密聚集在同一染色体位置，因此携带相似的细胞功能。我们认为miR-15 a/16介导巨噬细胞过度活化，并通过巨噬细胞释放的外泌体（细胞外囊泡）将炎症信号转运至远处靶点。miR-15 a/16的产生和封装到外泌体中需要PTRF，PTRF是一种在质膜和细胞核之间穿梭的新型脂筏蛋白。因此，我们已发表的研究表明，PTRF的缺失保护小鼠免受CLP后的SIRS/MOF/死亡和死亡的巨噬细胞衍生的NO/ROS。在该提议中，我们假设外泌体（EV）-穿梭miR-15 a/16在脓毒症诱导的SIRS及其相关的MOF中起关键作用。我们的研究可能为脓毒症后SIRS/MOF提供新的治疗和诊断靶点，这与临床实践高度相关。巨噬细胞是免疫系统的第一个防御武器，在炎症信号的传递和放大中起着至关重要的作用。因此，我们使用巨噬细胞作为细胞模型。盲肠结扎穿孔（CLP）用作体内脓毒症模型。我们将在以下具体目标中检验我们的假设：目的I：确定miR-15 a/16在体外巨噬细胞中的产生、分泌和调节。目的二：研究miR-15 a/16在体外巨噬细胞中的功能。目的III：探讨miR-15 a/16穿梭质粒在脓毒症中的作用。

DESCRIPTION (provided by applicant): Sepsis is a serious entity and the leading cause of death in the critically ill patients. It is characterized by a systemic inflammatory response syndrome (SIRS) and its associated multi-organ failure (MOF). The pathogenesis of sepsis associated SIRS/MOF is still poorly understood and therapeutic/diagnostic options remain limited. One of the remaining questions for the development of SIRS/MOF is how the focal infections are exaggerated to systemic inflammation. Based on our published and preliminary studies, we believe that exosomal-shuttle miRNAs play crucial roles in transporting inflammatory signals to the distant target cells and organs. miR-15a and miR-16 are clustered closely at the same chromosome position, thus, carrying similar cellular functions. We believe that miR-15a/16 mediate macrophage over-activation and transport the inflammatory signals to distant targets, via the macrophage released exosomes (extracellular vesicles). The generation and encapsulation of miR-15a/16 into the exosomes require PTRF, a novel lipid raft protein shuttling between plasma membrane and nuclei. Consistently, our published studies have demonstrated that deletion of PTRF protected mice from SIRS/MOF/death after CLP and deceased macrophage derived NO/ROS. In this proposal, we hypothesize that exosomal (EV)-shuttle miR-15a/16 plays crucial roles in sepsis induced SIRS and its associated MOF. Our studies potentially provide novel therapeutic and diagnostic targets for SIRS/MOF after sepsis, which is highly relevant to clinical practice. Macrophages, the first arm of defense in the immune system, play crucial roles in the transmission and amplification of inflammatory signals. Therefore, we use macrophages as the cellular models. Cecal ligation and puncture (CLP) is used as an in vivo sepsis model. We will test our hypotheses in the following specific aims: Aim I: To determine the generation, secretion and regulation of miR-15a/16 in macrophages in vitro. Aim II: To determine the cellular functions of miR-15a/16 in macrophages in vitro. Aim III: To determine the functional roles of exosomal (EV)- shuttle miR-15a/16 in sepsis in vivo.