MMP-8 Deficiency Improves Host Responses to Influenza Viral Infections

项目摘要/摘要 季节性流感每年在全球造成250-50万人死亡，死亡率在#年大幅上升。 大流行年。尽管流感疫苗是每年开发的，但只有49%的美国人口 在2010-2011年接种了疫苗，并不是所有受试者都对这些疫苗产生了强大的保护性免疫反应。 目前的抗病毒药物(如奥司他韦)只针对病毒，并不能预防流感相关的死亡。 在所有个人身上。因此，迫切需要开发更有效的治疗方法，以限制死亡率和 与甲型流感病毒(IAV)感染相关的高医疗负担。基质金属蛋白酶-8裂解亲- 炎症介质调节对各种刺激的炎症反应，但其对 IAV病的发病机制尚未得到评估。我的新奇初步数据强链接矩阵 金属蛋白酶-8(MMP8)对IAV感染动物不良结局的影响血浆基质金属蛋白酶-8水平为 在确诊为甲型H1N1大流行和季节性IAV感染的患者中显著上调，并且水平 与PaO2/FiO2比值呈负相关。H1N1流感患者肺组织中的基质金属蛋白酶-8水平也升高。 感染WT小鼠，定位于呼吸道上皮细胞和呼吸道巨噬细胞。与WT小鼠相比， MMP8-/-小鼠降低了H1N1禽流感病毒诱导的死亡率；降低了肺病毒载量；增加了肺组织中 I型干扰素(IFN)和活化的M1巨噬细胞的产物，以及增加的病毒性坏死性下垂 被感染的上皮细胞。因此，我们的数据首次将基质金属蛋白酶-8确定为一种新的治疗靶点 严重的IAV感染。这个博士后研究项目的目标是检验中心假说：基质金属蛋白酶-8 白细胞(巨噬细胞)缺乏可减少肺病毒负荷并改善IAV感染的预后 小鼠通过增加：1)M1巨噬细胞极化诱导更有效的(Th1)适应性免疫 对IAV的反应；2)肺巨噬细胞I型干扰素反应；以及3)I型干扰素诱导的IAV坏死性下垂。 被感染的上皮细胞，以限制IAV病毒的复制和传播。小分子基质金属蛋白酶-8抑制剂不是 有选择性，并有偏离目标的毒性作用。我们的研究还将确定一个新的纳米体在多大程度上 选择性抑制这种宿主蛋白的抑制剂(Nb14_NbAlb)在临床前模型中具有治疗效果 IAV感染。这些研究的成功完成将为未来的IND研究测试铺平道路 一流的针对宿主反应的治疗的安全性和有效性，以减少发病率和 与严重的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.