Department of Surgery.
Department of Molecular & Integrative Physiology, and.
JCI Insight. 2023 Sep 22;8(18):e166860. doi: 10.1172/jci.insight.166860.
Lung contusion and gastric aspiration (LC and GA) are major risk factors for developing acute respiratory distress following trauma. Hypoxia from lung injury is mainly regulated by hypoxia-inducible factor 1α (HIF-1α). Published data from our group indicate that HIF-1α regulation in airway epithelial cells (AEC) drives the acute inflammatory response following LC and GA. Metabolomic profiling and metabolic flux of Type II AEC following LC revealed marked increases in glycolytic and TCA intermediates in vivo and in vitro that were HIF-1α dependent. GLUT-1/4 expression was also increased in HIF-1α+/+ mice, suggesting that increased glucose entry may contribute to increased intermediates. Importantly, lactate incubation in vitro on Type II cells did not significantly increase the inflammatory byproduct IL-1β. Contrastingly, succinate had a direct proinflammatory effect on human small AEC by IL-1β generation in vitro. This effect was reversed by dimethylmalonate, suggesting an important role for succinate dehydrogenase in mediating HIF-1α effects. We confirmed the presence of the only known receptor for succinate binding, SUCNR1, on Type II AEC. These results support the hypothesis that succinate drives HIF-1α-mediated airway inflammation following LC. This is the first report to our knowledge of direct proinflammatory activation of succinate in nonimmune cells such as Type II AEC in direct lung injury models.
肺挫伤和胃吸入(LC 和 GA)是创伤后发生急性呼吸窘迫的主要危险因素。肺损伤引起的缺氧主要受缺氧诱导因子 1α(HIF-1α)调节。我们小组的已发表数据表明,气道上皮细胞(AEC)中的 HIF-1α调节会引发 LC 和 GA 后急性炎症反应。对 LC 后 II 型 AEC 的代谢组学分析和代谢通量分析显示,体内和体外的糖酵解和 TCA 中间产物明显增加,且依赖于 HIF-1α。HIF-1α+/+ 小鼠中的 GLUT-1/4 表达也增加,这表明增加的葡萄糖进入可能有助于增加中间产物。重要的是,体外培养的 II 型细胞中乳酸孵育并没有显著增加炎症副产物 IL-1β。相比之下,琥珀酸盐在体外对人小 AEC 具有直接的促炎作用,导致 IL-1β 的生成。二甲马来酸可逆转这种作用,这表明琥珀酸脱氢酶在介导 HIF-1α 效应中起着重要作用。我们证实了 II 型 AEC 上存在琥珀酸结合的唯一已知受体 SUCNR1。这些结果支持了这样一种假设,即琥珀酸盐会在 LC 后引发 HIF-1α 介导的气道炎症。据我们所知,这是首次在直接肺损伤模型中报道琥珀酸盐在非免疫细胞(如 II 型 AEC)中直接促炎激活的报告。