Immunoproteasome-Mediated Inflammation in Coronavirus Respiratory Infection

项目摘要 严重急性呼吸综合征冠状病毒2（SARS-CoV-2）是一种新型的人类冠状病毒， 导致2019冠状病毒病（COVID-19）大流行。COVID-19与严重的，经常 威胁生命的呼吸道疾病在很大一部分受影响的人。严重的COVID-19是 其特征在于对SARS-CoV-2感染的旺盛的全身炎症反应。这种反应有助于 在急性感染期间控制病毒复制，但它也驱动病毒诱导的病理和疾病 表现。由于尚不完全清楚的原因，有害的炎症反应是一种免疫反应。 在感染SARS-CoV-2的儿童中不太可能发生，儿童比成人更有可能发生 无症状感染者或病情轻微者。免疫蛋白酶体（IP）是泛素的诱导成分， 蛋白酶体系统，比组成型蛋白酶体更有效地产生MHC I类表位， 通过CD 8 T细胞识别。IP活性还对T细胞、B细胞、巨噬细胞和DC发挥内在作用 通过包括IκB降解和 随后NF-κ B介导的炎症通路活化。没有研究涉及 IP对人类或动物冠状病毒的发病机制。我们公布的和初步的数据表明， IP亚基活性在肺和其他器官中受到发育调节，随着年龄的增长而增加。IP亚基 在小鼠急性感染鼠冠状病毒期间表达增加，IP抑制抑制 病毒诱导的促炎细胞因子的表达，但增加体重减轻和死亡率。在这 根据这项提议，我们将检验一个假设，即冠状病毒感染期间IP活动的增加会推动 免疫病理学以年龄依赖的方式。我们将使用一种易于控制的动物模型， 冠状病毒，鼠肝炎病毒1型（MHV-1），以确定IP在冠状病毒发病机制中的作用， 鉴定IP抑制对急性感染期间病毒诱导的炎症和疾病的影响。目标1： 将定义急性MHV-1诱导的IP应答、炎症和疾病的年龄差异 呼吸道感染在目标2中，我们将使用IP亚基活性的药理学抑制来定义IP的作用。 对关键免疫细胞的活性，并确定IP在多大程度上有助于病毒诱导的炎症 和疾病显然迫切需要开发有效的预防和治疗方法 应对COVID-19的措施。对诱导型宿主因子（如IP）的调节，主要是活性的 在炎症状态如感染期间，如果它能促进减少 有害的炎症反应，对基本组成性活性宿主过程的影响最小。

PROJECT SUMMARY Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel human coronavirus that has caused the coronavirus disease 2019 (COVID-19) pandemic. COVID-19 is associated with severe, frequently life-threatening respiratory illness in a substantial proportion of affected people. Severe COVID-19 is characterized by an exuberant systemic inflammatory response to SARS-CoV-2 infection. That response aids in control of viral replication during acute infection, but it also drives virus-induced pathology and disease manifestations. For reasons that remain incompletely understood, that deleterious inflammatory response is less likely to develop in children infected with SARS-CoV-2, and children are more likely than adults to have asymptomatic infection or mild disease. The immunoproteasome (IP), an inducible component of the ubiquitin- proteasome system, is more efficient than the constitutive proteasome in generating MHC class I epitopes for recognition by CD8 T cells. IP activity also exerts intrinsic effects on T cell, B cell, macrophage, and DC functions and contributes to inflammatory responses via mechanisms that include degradation of IκB and subsequent activation of NF-κB-mediated inflammatory pathways. No studies have addressed contributions of the IP to the pathogenesis of human or animal coronaviruses. Our published and preliminary data suggest that IP subunit activity is developmentally regulated in the lungs and other organs, increasing with age. IP subunit expression increases in mice during acute infection with a murine coronavirus, and IP inhibition suppresses virus-induced expression of pro-inflammatory cytokines but enhances weight loss and mortality. In this proposal, we will test the hypothesis that increased IP activity during coronavirus infection drives immunopathology in an age-dependent manner. We will use a tractable animal model with an animal coronavirus, murine hepatitis virus type 1 (MHV-1), to define the role of the IP in coronavirus pathogenesis and identify effects of IP inhibition on virus-induced inflammation and disease during acute infection. In Aim 1, we will define age-based differences in IP response, inflammation, and disease induced by acute MHV-1 respiratory infection. In Aim 2, we will use pharmacologic inhibition of IP subunit activity to define effects of IP activity on key immune cells and determine the extent to which the IP contributes to virus-induced inflammation and disease. There is a clear and pressing need to development effective preventative and therapeutic measures for COVID-19. Modulation of an inducible host factor, such as the IP, that is predominantly active during an inflammatory state such as infection would be an appealing strategy if it could facilitate reduction of detrimental inflammatory responses with minimal impact on essential constitutively active host processes.