The role of innate immunity in downregulation of the airway antioxidant response during paramyxovirus infection

项目总结/摘要 本申请集中于先天免疫和抗病毒反应在免疫系统中的矛盾作用。 肺中关键细胞保护反应的失调。我们以前发现， 呼吸道合胞病毒（RSV）过程中活性氧（ROS）的不平衡产生 感染，婴儿下呼吸道感染（LRTI）的主要原因，是由进行性 转录因子NF-E2相关因子2（NRF 2）的核和细胞水平降低， 抗氧化酶（AOE）基因表达的调节因子。这一过程导致肺部疾病， 炎症，通过蛋白酶体途径通过NRF 2的脱乙酰化和增加降解而发生 并导致RSV感染的气道上皮细胞（AEC）中AOE表达减少，在实验中， 小鼠以及患有自然获得性RSV LRTI的儿童。RSV介导的NRF 2降解通过以下途径发生： 类小泛素化依赖性泛素连接酶RNF 4，被募集到早幼粒细胞白血病蛋白中 核小体（PML-NBs）在细胞氧化应激条件下。在缺乏IFN依赖性信号传导的情况下， 我们没有发现PML蛋白（PML-NB的主要成分）对RSV感染的应答诱导， 显著降低NRF 2降解，导致AOE基因表达增强。此外，缺乏 I型IFN受体（IFNR 1-/-）显示出显著的肺部炎症减轻和 临床疾病已知婴儿和幼儿的RSV感染对典型的 干扰素（IFN）的抗病毒活性，而肺和血液中IFN基因过表达的证据表明， 已被证明与免疫失调有关。此外，初步研究表明， NF-κB激活逆转RSV诱导的NRF 2乙酰化降低，恢复其细胞和核水平， 随后NRF 2依赖性基因转录和AOE基因表达增加。基于这些 数据，我们将测试这一假设，即RSV诱导的促炎和抗病毒途径在 RSV诱导的NRF 2死亡，导致肺氧化损伤和ROS依赖性疾病发病机制。 这些研究将提供初步的实验证据，表明干扰素途径的调节可能代表了一种新的干扰素途径。 RSV诱导的氧化性肺损伤和炎症的治疗干预的可能靶点。 .

PROJECT SUMMARY/ABSTRACT This application is focused on the paradoxical role of innate immune and antiviral responses in the dysregulation of critical cytoprotective responses in the lung. We have previously discovered that an unbalanced reactive oxygen species (ROS) production in the course of respiratory syncytial virus (RSV) infection, the major cause of lower respiratory tract infections (LRTI) in infants, is caused by a progressive reduction in nuclear and cellular levels of the transcription factor NF-E2-related factor 2 (NRF2), the primary regulator of antioxidant enzyme (AOE) gene expression. This process, which contributes to lung disease and inflammation, occurs through deacetylation and increased degradation of NRF2 via the proteasome pathway and leads to decreased expression of AOEs in RSV-infected airway epithelial cells (AECs), in experimental mice, as well as, in children with naturally acquired RSV LRTI. RSV-mediated NRF2 degradation occurs via the sumoylation-dependent ubiquitin ligase RNF4, which is recruited to the promyelocytic leukemia protein nuclear bodies (PML-NBs) in conditions of cellular oxidative stress. In the absence of IFN-dependent signaling, we found no induction of PML protein, a major component of PML-NBs, in response to RSV infection and significantly reduced NRF2 degradation, resulting in enhanced AOE gene expression. Moreover, mice lacking type I IFN receptor (IFNR1 -/-) display significant reduction of lung inflammation and overall improvement in clinical disease. RSV infection in infants and young children is known to be poorly responsive to the canonical antiviral activity of interferons (IFNs), whereas evidence of overexpression of IFN genes in lung and blood has been shown to be associated with immune dysregulation. In addition, preliminary studies indicated that lack of NF-κB activation revert RSV-induced decrease in NRF2 acetylation, restoring its cellular and nuclear levels, with subsequent increase in NRF2-dependent gene transcription and AOE gene expression. Based on these data, we will test the hypothesis that RSV-induced proinflammatory and antiviral pathways play a central role in the RSV-induced demise of NRF2, leading to lung oxidative injury and ROS-dependent disease pathogenesis. These studies will provide initial experimental evidence that modulation of the IFN pathway could represent a possible target for therapeutic intervention for RSV-induced oxidative lung damage and inflammation. .