Hydrogen Sulfide and NRF2 Cross-talk in Viral Infections

项目摘要/摘要 呼吸道合胞病毒(RSV)是引起我国上呼吸道和下呼吸道感染的主要原因。 儿童、老年人和免疫功能低下的宿主，没有有效的治疗或疫苗可用。 患有呼吸道合胞病毒引起的毛细支气管炎的儿童也有更高的反复喘息和 哮喘在晚年的发展。尽管RSV引起的疾病的发病机制仍然是一个问题 激烈的科学辩论，来自实验模型和自然获得性研究的越来越多的证据 感染表明，严重的下呼吸道感染确实与病毒“载量”增加和病毒延迟有关 由于先天免疫反应未能限制病毒复制而引起的清除，但会引起炎症和 组织损伤。内源性气体递质硫化氢(H_2S)与多种 炎症和血管紊乱，与促炎和抗炎信号有关。最近， 我们小组收集了重要的新数据、试剂和动物模型，证明了硫化氢的关键作用 在调节肺部的抗病毒和抗炎反应方面。特别是，我们已经证明了硫化氢 有效抑制病毒复制，发挥抗炎活性，并控制呼吸道高反应性 RSV感染的小鼠。在细胞水平上，我们已经证明RSV能够抑制 胱硫醚γ裂解酶(CSE)，产生硫化氢的关键酶是肺，降低了产生硫化氢的能力 细胞内的硫化氢。我们认为，硫化氢途径的失调会影响宿主的抗病毒反应，并在 在严重呼吸道合胞病毒感染的发病机制中起关键作用。我们的发现表明了一个重要的串音 H_2S和转录因子NF-E2相关因子2(NRF2)依赖的途径，控制细胞 氧化还原平衡，它们每一个都对另一个产生积极的影响，它们都被下调了 在RSV感染过程中。因此，在这个项目中，我们将检验中心假设，即抑制 由于NRF2依赖的基因转录减少，细胞保护性硫化氢的产生导致临床 呼吸道合胞病毒感染的表现。我们将采用体外和体内相结合的方法来测试这一点。 假说，通过使用NRF2或H2S生成酶基因缺陷的细胞和小鼠，以及 有机会接触到我们持续感染呼吸道合胞病毒的婴幼儿。这个项目将 阐明呼吸道病毒调节肺部疾病的先天途径，对 开发新的抗病毒和抗炎治疗策略治疗RSV诱导的LRTI，并可能 长期后果，如反复喘息或哮喘。我们长期的临床和研究 在病毒性毛细支气管炎和呼吸道合胞病毒感染的发病机制方面的专业知识，强大的初步数据，以及 UTMB在肺部疾病领域的卓越资源使我们非常适合追求这一创新 项目。

PROJECT SUMMARY/ABSTRACT Respiratory syncytial virus (RSV) is a major cause of upper and lower respiratory tract infections (LRTIs) in children, elderly and immunocompromised hosts, for which no effective treatment or vaccine is available. Children who develop RSV-induced bronchiolitis are also at increased risk for recurrent wheezing and development of asthma in later life. Although the pathogenesis of RSV-induced disease remains a matter of intense scientific debate, increasing evidence from experimental models and studies in naturally acquired infections suggest that severe LRTIs are indeed associated with increased viral “load” and delayed viral clearance due to an innate immune response that fails to restrict viral replication, yet causing inflammation and tissue damage. The endogenously-generated gasotransmitter hydrogen sulfide (H2S) is implicated in a variety of inflammatory and vascular disorders, associated with both pro- and anti-inflammatory signaling. Recently, our group has gathered important new data, reagents and animals models that demonstrate a key role of H2S in mediating antiviral and anti-inflammatory responses in the lung. In particular, we have shown that H2S potently inhibits viral replication, exerts anti-inflammatory activity, and controls airway hyperresponsiveness in RSV-infected mice. At the cellular level, we have shown that RSV is capable of inhibiting the expression of cystathionine γ-lyase (CSE), the key enzyme that generates H2S is the lung, reducing the ability to generate cellular H2S. We propose that dysregulation of the H2S pathway affects host antiviral response and plays a critical role in the pathogenesis of severe RSV infections. Our findings indicate an important cross-talk between H2S and the transcription factor NF-E2-related factor 2 (NRF2)-dependent pathways, which control the cellular redox balance, each of them exerting a positive influence on the other, and both of them being downregulated in the course of RSV infection. Thus, in this project, we will test the central hypothesis that inhibition of cytoprotective H2S generation, due to decreased NRF2-dependent gene transcription, leads to clinical manifestations of RSV infection. We will employ a combination of in vitro and in vivo approaches to test this hypothesis, by the use of cells and mice genetically deficient in either NRF2 or H2S generating enzymes, and the access to our ongoing cohort of infants and young children with primary RSV infections. This project will elucidate innate pathways by which respiratory viruses modulate lung disease, with strong implications for developing novel antiviral and anti-inflammatory therapeutic strategies for RSV-induced LRTI and possibly long-term consequences, such as recurrent wheezing or asthma. Our long-standing clinical and research expertise in the area of pathogenesis of viral bronchiolitis and RSV infections, strong preliminary data, and UTMB's outstanding resources in the area of lung disease make us ideally suited to pursue this innovative project.