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

项目摘要/摘要 这一应用主要集中在先天免疫和抗病毒反应在疾病中的矛盾作用。 肺内关键细胞保护反应的失调。我们之前已经发现， 呼吸道合胞病毒(RSV)感染过程中ROS的失衡产生 感染是婴儿下呼吸道感染(LRTI)的主要原因，由渐进性 转录因子NF-E2相关因子2(NRF2)的核和细胞水平降低，NRF2是主要的 抗氧化物酶(AOE)基因表达的调节。这一过程会导致肺部疾病和 炎症，通过蛋白酶体途径去乙酰化和增加NRF2的降解而发生 并导致呼吸道合胞病毒感染的呼吸道上皮细胞(AECs)AOES表达降低。 小鼠，以及自然获得RSV LRTI的儿童。RSV介导的NRF2降解通过 苏莫化依赖的泛素连接酶RNF4，招募到早幼粒细胞白血病蛋白 核体(PML-NBS)在细胞氧化应激条件下。在缺乏干扰素依赖信号的情况下， 我们没有发现PML-NBS的主要成分PML蛋白在RSV感染和 显著降低NRF2的降解，导致AOE基因表达增强。此外，老鼠缺乏 I型干扰素受体(IFNR1-/-)显示出显著减轻肺部炎症和全面改善 临床疾病。众所周知，婴儿和幼儿中的RSV感染对规范的 干扰素的抗病毒活性，而有证据表明干扰素基因在肺和血液中过表达。 已被证明与免疫失调有关。此外，初步研究表明，缺乏 NF-κB的激活逆转了呼吸道合胞病毒引起的NRF2乙酰化水平的下降，恢复了其细胞和核水平， 随后NRF2依赖的基因转录和AOE基因表达增加。基于这些 数据，我们将检验假设，即RSV诱导的促炎和抗病毒途径在 RSV诱导NRF2的死亡，导致肺氧化损伤和ROS依赖性疾病的发病机制。 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着一种 可能作为RSV引起的氧化性肺损伤和炎症的治疗干预的靶点。 。

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. .