S-nitrosothiols, NF-KappaB and Inflammation in Acute Lung Injury

说明(申请人提供)：S亚硝硫醇(SNO)是一种稳定的、具有生物活性的一氧化氮(NO)化合物，在肺部发现浓度较高。通过抑制转录因子NF-(B)的激活，SNO改变了免疫反应，有证据表明，气道SNO水平的波动有助于调节肺部炎症。S-亚硝基谷胱甘肽还原酶和一氧化氮合酶分别是通过增加SNO代谢和合成来控制肺中SNO浓度的酶。在这方面，内毒素诱导的NF-B活性和呼吸道炎症在诱导型一氧化氮合酶(NOS2)缺失(KO)小鼠的肺中增加，在GSNOR KO小鼠的肺中减弱。此外，亚硝酸乙酯(ENO)补充肺SNO可抑制内毒素诱导的NF-B活性和炎症反应。鉴于这些观察，我们假设SNO通过抑制NF-(B)途径的活性来减轻肺部炎症。为了验证这一假说，我们制定了以下具体目标：1.确定SNO代谢在调节肺部炎症中的重要性。2.确定SNO在调节肺组织中的NF-B信号转导中的作用。3.探讨肺SNO再灌流对肺组织炎症及核因子-B活性的影响。比较C57BL6野生型(WT)、NOS2 KO、NOS3 KO和GSNOR KO小鼠对雾化内毒素的肺炎症反应。肺和气道液中的SNO水平将被量化，并与肺部炎症和核因子-B活性的病理决定因素相关。我们将确定核因子-B信号转导通路中对SNO敏感的特定步骤(S)，并分析调节这些步骤的蛋白质，以便通过S亚硝化进行翻译后修饰。还将检测吸入ENO和常规NO气体治疗对内毒素暴露的WT小鼠这些参数的影响。实现这些目标将阐明SNO代谢在肺损伤炎症反应演变中的重要性，并进一步阐明SNO调节免疫反应的分子机制(S)。然后，这些数据可以转化为治疗急性肺损伤的新治疗策略。公共卫生相关性：急性肺损伤(ALI)或急性呼吸窘迫综合征(ARDS)是一种疾病，在美国每年的发病率约为19万例，死亡率在40%-50%之间。尽管具有临床意义，但ALI/ARDS的病理生理机制仍然知之甚少，治疗仅限于支持性护理。这项研究建议将解决被称为S亚硝硫醇的内源性分子在控制与ALI/ARDS相关的炎症方面的重要性。从拟议的研究中获得的知识可能会导致针对ALI/ARDS和其他肺部疾病炎症的新疗法的开发。

DESCRIPTION (provided by applicant): S-nitrosothiols (SNO) are stable, bioactive nitric oxide (NO) compounds found at high concentration in the lung. By inhibiting activation of the transcription factor NF-(B, SNO alters the immune response with evidence suggesting that fluctuation in airway SNO levels serves to regulate pulmonary inflammation. S-nitrosoglutathione reductase (GSNOR) and nitric oxide synthase (NOS) are enzymes that control lung SNO concentrations by increasing SNO metabolism and production respectively. In this regard, LPS-induced NF-(B activity and airway inflammation is augmented in the lungs of inducible NOS (NOS2)-null (KO) mice and diminished in the lungs of GSNOR KO mice. Furthermore, lung SNO repletion by ethyl nitrite (ENO) gas inhibits LPS-induced NF-(B activity and inflammation. Given these observations, we hypothesize that SNO serves to attenuate lung inflammation by inhibiting activity in the NF-(B pathway. To test this hypothesis, we have formulated the following specific aims: 1. Determine the importance of SNO metabolism in the regulation of lung inflammation. 2. Determine the role of SNO in modulating NF-(B signaling in the lung. 3. Investigate the effect of lung SNO repletion on lung inflammation and NF-(B activity. The pulmonary inflammatory response of C57BL6 wild-type (WT), NOS2 KO, NOS3 KO and GSNOR KO mice to aerosolized LPS will be contrasted. SNO levels (in the lung and airway fluid) will be quantified and correlated to pathological determinants of lung inflammation and NF-(B activity. The specific step(s) in the NF-(B signal transduction pathway that are sensitive to SNO will be identified and the proteins that regulate these steps analyzed for post-translational modification by S-nitrosylation. The effect of treatment with inhaled ENO and conventional NO gas on these parameters in LPS-exposed WT mice will also be examined. Accomplishing these aims will delineate the importance of SNO metabolism in the evolution of inflammation in response to lung injury and further elucidate the molecular mechanism(s) by which SNO modulates the immune response. These data could then translate into new therapeutic strategies in the treatment of acute lung injury. PUBLIC HEALTH RELEVANCE: Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a disease with an annual incidence in the United States of approximately 190,000 cases and a mortality rate between 40-50%. Despite its clinical significance, the pathophysiology of ALI/ARDS remains poorly understood with treatment limited to supportive care. This research proposal will address the importance of endogenously-produced molecules termed S-nitrosothiols, in controlling the inflammation that is associated with ALI/ARDS. The knowledge gained from the proposed studies could lead to the development of new therapies that target inflammation in ALI/ARDS and other pulmonary disorders..