Targeting TLR Signaling Pathways to Blunt Pathogen-mediated Acute Lung Injury

几十年来，“一种细菌、一种药物”的方法一直是疫苗或治疗方法发展的特征。 特定的传染病。我们根据新的治疗方法的发展提出了一种不同的方法 通过利用在流感和其他优先病原体感染期间触发的常见宿主先天免疫反应，来控制传染病。全球每年有多达500万人感染流感病毒， 造成多达50万人死亡。我们强有力的实验证据表明，强大的TLR4拮抗剂， 厄立特里亚(Eisai，Inc.)以及其他多种TLR4拮抗剂显著减轻了两种急性肺损伤 (ALI)和死亡率，当给药治疗流感感染的小鼠。厄立特里亚不仅阻止流感介导的宿主衍生的“危险相关分子模式”(DAMPS)的释放，而且还钝化了 在巨噬细胞中，潮湿介导的TLR4信号通常会导致“细胞因子风暴”。当我们有了 阐明了流感介导ALI和致死率的几种新机制，这些机制被 厄立特里亚疗法(例如，释放宿主衍生的通过TLR4传递信号的阻滞剂；导致肺水肿的紧密连接通透性增加；IL-1α/β在致命性中的作用)，我们对整体先天 控制流感引起的ALI和厄立特里亚介导的保护的免疫信号通路仍然不完整，需要进一步研究以开发高效的宿主导向疗法。因此， 具体目标1将侧重于确定作为流感敏感性和厄立特里亚介导保护的基础的先天免疫机制。我们将利用转基因小鼠品系来解剖 信号通路接合了。TLR4是否必须在基质细胞和/或髓系细胞上表达，其作用 湿释放中病毒诱导的上皮细胞坏死性下垂的研究，非TLR4PRR的作用机制 与流感耐药性/敏感性有关，以及宿主需要TLR2/TLR4二聚化的可能性 对流感的反应将被评估为可用于提高治疗效果的新的潜在机制。在特定目标2中，一种新的IKKβ抑制剂E6070(卫材公司)的治疗益处 流感单独或在目前的抗流感抗病毒疗法存在的情况下，将在棉鼠身上进行测试。 (Cr)，这是第二种啮齿动物物种，可以分析ALI对未适应的人类流感分离株感染的反应。AIM 2还将在继发性葡萄球菌模型中比较厄立特里亚和E6070的CR (MRSA)流感感染后的肺炎。最后，我们将评估厄立特里亚的相对效力。 和E6070用于阻断由其他临床重要或生物治疗相关病原体引起的ALI的能力 首先是在小鼠身上，如果有效，在CR中使用ALI(如图拉氏方济氏菌、肺炎链球菌、肺炎克雷伯氏菌、SARS冠状病毒和MERS冠状病毒)。这些实验将挑战最重要的 中心假设TLR拮抗剂代表基础广泛的治疗药物，可减轻病理变化 寄主对多种诱导ALI的优先病原菌的反应。

For decades, a “one bug, one drug” approach has characterized development of vaccines or treatments for specific infectious diseases. We propose a different approach based on the development of novel treatment of infectious diseases by capitalizing on common host innate immune responses that are triggered during infection by influenza and other priority pathogens. Influenza virus infects up to 5 million people yearly worldwide, killing as many as ~500,000. Our strong experimental evidence demonstrates that the potent TLR4 antagonist, Eritoran (Eisai, Inc.), as well as multiple other TLR4 antagonists, significantly decreased both acute lung injury (ALI) and mortality when administered therapeutically to influenza-infected mice. Eritoran not only blocks influenza-mediated release of host-derived ”danger-associated molecular patterns” (DAMPs), but also blunted DAMP-mediated TLR4 signaling in macrophages that normally results in a “cytokine storm.” While we have elucidated several novel mechanisms by which influenza mediates ALI and lethality that are counteracted by Eritoran therapy (e.g., release of host-derived DAMPS that signal through TLR4; increased tight-junction permeability leading to pulmonary edema; a role for IL-1α/β in lethality), our understanding of the overall innate immune signaling pathways that control influenza-induced ALI and Eritoran-mediated protection remains incomplete, necessitating further investigation to develop a highly efficacious host-directed therapy. Therefore, Specific Aim 1 will focus on the identification of innate immune mechanisms that underlie both influenza sensitivity and Eritoran-mediated protection. We will take advantage of genetically modified mouse strains to dissect the signaling pathways engaged. Whether TLR4 must be expressed on stromal and/or myeloid cells, the role of virus-induced epithelial cell necroptosis in DAMP release, mechanisms by which non-TLR4 PRRs contribute to influenza resistance/susceptibility, and the possibility that TLR2/TLR4 dimerization is required for the host response to influenza will be evaluated as novel potential mechanisms that can be exploited to enhance therapeutic efficacy. In Specific Aim 2, the therapeutic benefit of a novel IKKβ inhibitor, E6070 (Eisai, Inc.), against influenza, alone or in the presence of current anti-influenza antiviral therapies, will be tested in cotton rats (CR), a second rodent species that permits analysis of ALI in response to infection by non-adapted human influenza isolates. Aim 2 will also compare Eritoran and E6070 in CR in a model of secondary staphylococcal (MRSA) pneumonia following influenza infection. Lastly, we will assess the relative effectiveness of Eritoran and E6070 for the ability to block ALI caused by other clinically important or biothreat pathogens associated with ALI in humans (e.g., Francisella tularensis, Streptococcus pneumoniae, Klebsiella pneumoniae, SARS-CoV and MERS-CoV), first in mice, and, if effective, in CR. These experiments will challenge the overarching central hypothesis that TLR antagonists represent broad-based, therapeutic agents that mitigate pathologic host responses to multiple ALI-inducing priority pathogens.