EARLY ENDOTOXIN TOLERANCE: CELLULAR/MOLECULAR MECHANISMS

描述（改编自申请人摘要）：脓毒症和脓毒性休克 是重要的临床问题，约有50万例，80亿美元的 每年的医疗费用。这一问题在密集型 护理环境和免疫功能低下的患者脂多糖（LPS）， 革兰氏阴性菌的内毒素外膜成分，长期以来一直是 作为脓毒症死亡率的主要影响因素， 炎症细胞因子的过度产生， LPS与宿主巨噬细胞的相互作用。迄今为止，治疗干预 靶向LPS或单个LPS诱导的细胞因子已经被 失望因此，了解LPS作用机制， 分子和细胞水平仍然是重要的研究领域。 与此相关的是，我们描述了 “早期内毒素耐受性”（EET），一种公认的，但了解甚少的 导致对后续LPS不应的状态的现象 exposure.在体外，巨噬细胞对随后的LPS的“耐受”状态 可以通过用LPS预处理巨噬细胞来实现刺激。最近 研究为“容忍”某些人的概念提供了强有力的支持。 LPS反应伴随着活性增加，如通过其他LPS评估的那样。 反应，从而导致一个更普遍的概念“重编程。" 然而，体内EET与巨噬细胞“重编程”之间的关系尚不清楚。 vitro不了解该提案详细介绍了新的实验方法， 定义介导EET的事件。待检验的总体假设是， LPS与宿主巨噬细胞的初始相互作用启动了一个遗传过程， 通过选择性调节前-和后-的盒来“重编程”。 抗炎介质基因，反过来，定义EET表型。的 研究人员进一步假设，选择性影响 通过“重编程”深刻地影响革兰氏阴性菌感染的过程。 他们的具体目标是：（1）剖析具体的 巨噬细胞亚群和基因已经涉及这一过程，（2）确定 新的基因，有助于EET和评估EET对脓毒症的影响， 和（3）分析特定的细胞内途径，以了解它们在细胞内的潜在作用。 诱导/维持“耐受性”。“预计， 本研究旨在探讨内毒素耐受的机制及其对机体免疫功能的潜在影响。 将更好地理解脓毒症和其他疾病的疾病结果。

DESCRIPTION (Adapted from the Applicant's Abstract): Sepsis and septic shock are important clinical problems, with about 500,000 cases and $8 billion in health care costs annually. This problem is exacerbated within the intensive care setting and in immunocompromised patients Lipopolysaccharide (LPS), the endotoxic outer membrane component of Gram negative bacteria, has long been implicated as a major contributing factor to mortality in sepsis, due largely to the overproduction of inflammatory cytokines that is initiated by the interaction of LPS with host macrophages. To date, therapeutic intervention targeting either LPS or individual LPS-induced cytokines has been disappointing. Thus, an understanding of the mechanisms of LPS action at the molecular and cellular level remain a significant area of investigation. Pivotal to this understanding is a delineation of molecular mechanisms of "early endotoxin tolerance" (EET), a well recognized, but poorly understood phenomenon that results in a state of refractoriness to subsequent LPS exposure. In vitro, a state of macrophage "tolerance" to subsequent LPS stimulation can be achieved by pre-treatment of macrophages with LPS. Recent studies have provided strong support for the concept that "tolerance" to some LPS responses is accompanied by increased activity as assessed by other LPS responses, thus leading to a more generalized concept of "reprogramming." However, the relationship between EET in vivo and macrophage "reprogramming" in vitro is not understood. This proposal details novel experimental approaches to define events that mediate EET. The overall hypothesis to be tested is that the initial interaction of LPS with host macrophages initiates a process of genetic "reprogramming" via selective modulation of a cassette of pro- and anti-inflammatory mediator genes that, in turn, defines the EET phenotype. The investigators further hypothesize that products of genes selectively affected by "reprogramming" profoundly influence the course of Gram negative infection. Their Specific Aims are designed to (1) dissect the contribution of specific macrophage subsets and genes already implicated in this process, (2) identify novel genes that contribute to EET and to evaluate the impact of EET on sepsis, and (3) analyze specific intracellular pathways for their potential role in the induction/maintenance of "tolerance." It is expected that, at the conclusion of this research, the mechanism of endotoxin tolerance and its potential impact on disease outcome in both sepsis and other diseases will be better understood.