Molecular Mechanisms of LPS Preconditioning In Stroke

描述（由申请人提供）：脑缺血是美国发病率和死亡率的主要原因之一，许多缺血病例继发于心血管手术。用toll样受体激动剂LPS预处理或预处理可诱导对缺血损伤的保护性反应，即缺血耐受。这个竞争性更新应用程序旨在阐明由LPS预处理诱导的定义缺血耐受的分子事件。我们之前的研究揭示了一个新的基因组指纹，暗示I型干扰素（ifn）是LPS诱导的缺血性损伤耐受的主要效应物。我们发现IFN转录因子IRF3是LPS预处理所必需的，我们最近的初步工作表明IFN转录因子IRF7也可能是必需的。此外，我们发现IFN基因组指纹延伸到由另外两种预处理刺激诱导的脑缺血保护：TLR9配体，未甲基化的CpG ODNs和低剂量缺血，从而扩大了其重要性。神经保护中新的IFN指纹的出现支持了一种新的预处理工作模型，其中toll样受体是中心特征。阐明IFN反应的功能可能有助于深入了解TLR诱导的卒中预防性治疗机制，并导致TLR诱导的急性神经保护新途径的发展，该途径绕过了预先预处理的需要。这些发现使我们假设LPS预处理通过IRF3/IRF7驱动的一组核心基因的表达诱导神经保护，从而导致神经保护的互补途径。我们将在三个目标中测试这个模型的规则及其治疗潜力：阐明转录因子IRF3和IRF7在tlr诱导的神经保护中的作用。目标2。确定IFN指纹图谱对缺血性损伤的神经保护机制。目标3。检测IRF3/7在脑卒中急性期的直接激活是否导致缺血性神经保护。

DESCRIPTION (provided by applicant): Brain ischemia is one of the leading causes of morbidity and mortality in the United States, and many cases of ischemia are secondary to cardiovascular surgery. Pretreatment or preconditioning with a Tol-like Receptor agonist, LPS, induces a protective response to ischemic injury referred to as ischemic tolerance. This competitive renewal application seeks to elucidate the molecular events that define ischemic tolerance induced by LPS preconditioning. Our previous research revealed a novel genomic fingerprint that implicates type I interferons (IFNs) as primary effectors of LPS induced tolerance to ischemic injury. We discovered that the IFN transcription factor, IRF3 is required for LPS preconditioning and our recent preliminary work suggests that the IFN transcription factor, IRF7 may also be required. In addition we have found that the IFN genomic fingerprint extends to ischemic protection of the brain induced by two other preconditioning stimuli: a TLR9 ligand, unmethylated CpG ODNs and low dose ischemia thus broadening its importance. The appearance of a novel IFN fingerprint in neuroprotection supports a new working model of preconditioning in which Toll-like receptors are the central feature. Elucidation of the function of the IFN response may provide insight into the mechanism of TLR induced prophylactic treatment for stroke and lead to the development of a new TLR induced pathway of acute neuroprotection that by-passes the need for prior preconditioning. These findings have led us to hypothesize that LPS preconditioning induces neuroprotection through IRF3/IRF7 driven expression of a core set of genes that result in complimentary pathways of neuroprotection. We shall test the precepts of this model and its therapeutic potential in three aims: Aim 1. Elucidate the function of transcription factors IRF3 and IRF7 in TLR-induced neuroprotection. Aim 2. To determine the mechanism by which the IFN fingerprint confers neuroprotection in response to ischemic injury. Aim 3. Test whether direct activation of IRF3/7 in the acute setting of stroke leads to ischemic neuroprotection.