Preterm infants and patients with lung disease often have excess fluid in the lungs and are frequently treated with oxygen, however long-term exposure to hyperoxia results in irreversible lung injury. Although the adverse effects of hyperoxia are mediated by reactive oxygen species, the full extent of the impact of hyperoxia on redox-dependent regulation in the lung is unclear. In this study, neonatal mice overexpressing the beta-subunit of the epithelial sodium channel (β-ENaC) encoded by Scnn1b and their wild type (WT; C57Bl6) littermates were utilized to study the pathogenesis of high fraction inspired oxygen (FiO₂)-induced lung injury. Results showed that O₂-induced lung injury in transgenic Scnn1b mice is attenuated following chronic O₂ exposure. To test the hypothesis that reversible cysteine-redox-modifications of proteins play an important role in O₂-induced lung injury, we performed proteome-wide profiling of protein S-glutathionylation (SSG) in both WT and Scnn1b overexpressing mice maintained at 21% O₂ (normoxia) or FiO₂ 85% (hyperoxia) from birth to 11–15 days postnatal. Over 7700 unique Cys sites with SSG modifications were identified and quantified, covering more than 3000 proteins in the lung. In both mouse models, hyperoxia resulted in a significant alteration of the SSG levels of Cys sites belonging to a diverse range of proteins. In addition, substantial SSG changes were observed in the Scnn1b overexpressing mice exposed to hyperoxia, suggesting that ENaC plays a critically important role in cellular regulation. Hyperoxia-induced SSG changes were further supported by the results observed for thiol total oxidation, the overall level of reversible oxidation on protein cysteine residues. Differential analyses reveal that Scnn1b overexpression may protect against hyperoxia-induced lung injury via modulation of specific processes such as cell adhesion, blood coagulation, and proteolysis. This study provides a landscape view of protein oxidation in the lung and highlights the importance of redox regulation in O₂-induced lung injury.

早产儿和患有肺部疾病的患者通常肺部有过多液体，经常接受氧气治疗，但长期暴露于高氧环境会导致不可逆的肺损伤。尽管高氧的不利影响是由活性氧介导的，但高氧对肺部氧化还原依赖性调节的影响的全部程度尚不清楚。在本研究中，利用过度表达Scnn1b编码的上皮钠通道 β 亚基 (β-ENaC) 的新生小鼠及其野生型 (WT; C57Bl6) 同窝小鼠来研究高分数吸入氧 (FiO ₂ ) 的发病机制 -诱发肺损伤。结果表明，转基因Scnn1b 小鼠中O _{2诱导的肺损伤在慢性O 2}暴露后减弱。为了检验蛋白质的可逆半胱氨酸氧化还原修饰在 O _{2诱导的肺损伤中发挥重要作用的假设，我们对 WT 和}Scnn1b过表达小鼠（维持在 21%）中进行了蛋白质 S-谷胱甘肽 (SSG) 的全蛋白质组分析。从出生到出生后 11-15 天，O ₂（含氧量正常）或 FiO _{2 85%（高氧）。}鉴定并定量了超过 7700 个带有 SSG 修饰的独特 Cys 位点，覆盖了肺部的 3000 多种蛋白质。在这两种小鼠模型中，高氧导致属于多种蛋白质的 Cys 位点的 SSG 水平显着改变。此外，在暴露于高氧的Scnn1b过表达小鼠中观察到显着的 SSG 变化，表明 ENaC 在细胞调节中发挥着至关重要的作用。硫醇总氧化（蛋白质半胱氨酸残基可逆氧化的总体水平）观察到的结果进一步支持高氧诱导的 SSG 变化。差异分析表明，Scnn1b过度表达可能通过调节细胞粘附、凝血和蛋白水解等特定过程来防止高氧诱导的肺损伤。这项研究提供了肺部蛋白质氧化的全景图，并强调了氧化还原调节在 O ₂诱导的肺损伤中的重要性。