MMP-8 Deficiency Improves Host Responses to Influenza Viral Infections

项目总结/摘要 季节性流感每年在全世界造成25 - 50万人死亡， 大流行年。尽管每年都在开发流感疫苗，但只有49%的美国人口接种了流感疫苗。 在2010-2011年接种了疫苗的受试者中，并不是所有受试者都对这些疫苗产生了强有力的保护性免疫应答。 目前的抗病毒药物（如奥司他韦）仅针对病毒，不能预防流感相关死亡 在所有个体中。因此，迫切需要开发更有效的治疗方法，以限制死亡率， 与甲型流感病毒（IAV）感染相关的高卫生保健负担。MMP-8切割前体， 炎症介质调节炎症反应的各种刺激，但其贡献的 IAV疾病的发病机制尚未评估。我的小说初步数据将矩阵 金属蛋白酶-8（Mmp-8）对感染IAV动物的不良结局的影响。血浆MMP-8水平是 在诊断为大流行性H1N1和季节性IAV感染的患者中显著上调， 与PaO 2/FiO 2比值呈负相关。Mmp-8肺水平也在H1N1患者的肺中增加， 感染WT小鼠，并定位于气道上皮细胞和气道巨噬细胞。与WT小鼠相比， Mmp-8-/-小鼠具有降低的H1N1 IAV诱导的死亡率;降低的肺病毒负荷;增加的肺病毒水平。 I型干扰素（IFN）和活化的M1巨噬细胞的产物，以及增加的病毒性 感染的上皮细胞因此，我们的数据首次确定MMP-8作为一种新的治疗靶点， 严重的IAV感染。这个博士后奖学金的目标是测试中心假设：Mmp-8 白细胞（巨噬细胞）缺乏可降低IAV感染者的肺病毒负荷并改善其预后 通过增加小鼠：1）M1巨噬细胞极化以诱导更有效的（Th 1）适应性免疫 对IAV的反应; 2）肺巨噬细胞I型IFN反应;和3）I型IFN诱导的IAV的坏死性凋亡。 感染的上皮细胞，以限制IAV病毒的复制和传播。小分子MMP-8抑制剂不是 具有选择性和脱靶毒性作用。我们的研究还将确定一种新型纳米抗体 选择性抑制该宿主蛋白的抑制剂（Nb14_NbAlb）在以下临床前模型中具有治疗功效： IAV感染。这些研究的成功完成将为未来的IND使能研究铺平道路， 针对宿主反应的“一流”治疗方法的安全性和有效性，以降低发病率和 与严重IAV感染相关的死亡率。

Project Summary/ Abstract Seasonal influenza causes 0.25-0.5 million deaths/year world-wide and mortality increases substantially in pandemic years. Although influenza vaccines are developed annually, only 49% of the US population was vaccinated in 2010-2011, and not all subjects develop robust protective immune responses to these vaccines. Current anti-viral drugs (e.g. oseltamivir) target only the virus and do not prevent influenza-associated mortality in all individuals. Thus, there is an urgent need to develop more effective therapies that limit the mortality and high health care burden that are associated with influenza A viral (IAV) infections. MMP-8 cleaves pro- inflammatory mediators to regulate inflammatory responses to various stimuli, but its contributions to the pathogenesis of IAV disease have not been evaluated. My novel preliminary data strongly link Matrix metalloproteinase-8 (Mmp-8) to adverse outcomes in animals infected with IAV. Plasma MMP-8 levels are significantly upregulated in patients diagnosed with pandemic H1N1 and seasonal IAV infections, and levels correlate inversely with the PaO2/FiO2 ratio. Mmp-8 lung levels are also increased in the lungs of H1N1- infected WT mice and localized to airway epithelial cells and airway macrophages. Compared with WT mice, Mmp-8-/- mice have reduced H1N1 IAV-induced mortality; lower lung viral burdens; increased lung levels of type I interferons (IFNs) and products of activated M1 macrophages, and increased necroptosis of virally- infected epithelial cells. Thus, our data identifying MMP-8 for the first time as a novel therapeutic target during serious IAV infections. The goal of this postdoctoral fellowship is to test the central hypotheses: Mmp-8 deficiency in leukocytes (macrophages) reduces lung viral burdens and improves outcomes in IAV-infected mice by increasing: 1) M1 macrophage polarization to induce a more effective (Th1) adaptive immune response to IAV; 2) the lung macrophage type I IFN response; and 3) type I IFN induced-necroptosis of IAV- infected epithelial cells to limit IAV viral replication and spreading. Small molecule MMP-8 inhibitors are not selective and have off-target toxic effects. Our studies will also determine the extent to which a novel nanobody inhibitor (Nb14_NbAlb) that selectively inhibits this host protein has therapeutic efficacy in a pre-clinical model of IAV infection. Successful completion of these studies will pave the way for future IND-enabling studies to test the safety and efficacy of a “first in class” therapeutic targeting the host response to reduce the morbidity and mortality associated with serious IAV infections.