Hoegl Sandra, Brodsky Kelley S, Blackburn Michael R, Karmouty-Quintana Harry, Zwissler Bernhard, Eltzschig Holger K
Organ Protection Program, Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045; Department of Anesthesiology, Comprehensive Pneumology Center Munich, German Center for Lung Research, University Hospital, Ludwig Maximilian University, D-81377 Munich, Germany; and
Organ Protection Program, Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045;
J Immunol. 2015 Aug 15;195(4):1815-24. doi: 10.4049/jimmunol.1401957. Epub 2015 Jul 17.
Acute lung injury (ALI) is an acute inflammatory lung disease that causes morbidity and mortality in critically ill patients. However, there are many instances where ALI resolves spontaneously through endogenous pathways that help to control excessive lung inflammation. Previous studies have implicated the extracellular signaling molecule adenosine and signaling events through the A2B adenosine receptor in lung protection. In this context, we hypothesized that tissue-specific expression of the A2B adenosine receptor is responsible for the previously described attenuation of ALI. To address this hypothesis, we exposed mice with tissue-specific deletion of Adora2b to ALI, utilizing a two-hit model where intratracheal LPS treatment is followed by injurious mechanical ventilation. Interestingly, a head-to-head comparison of mice with deletion of Adora2b in the myeloid lineage (Adora2b(loxP/loxP) LysM Cre(+)), endothelial cells (Adora2b(loxP/loxP) VE-cadherin Cre(+)), or alveolar epithelial cells (Adora2b(loxP/loxP) SPC Cre(+)) revealed a selective increase in disease susceptibility in Adora2b(loxP/loxP) SPC Cre(+) mice. More detailed analysis of Adora2b(loxP/loxP) SPC Cre(+) mice confirmed elevated lung inflammation and attenuated alveolar fluid clearance. To directly deliver an A2B adenosine receptor-specific agonist to alveolar epithelial cells, we subsequently performed studies with inhaled BAY 60-6583. Indeed, aerosolized BAY 60-6583 treatment was associated with attenuated pulmonary edema, improved histologic lung injury, and dampened lung inflammation. Collectively, these findings suggest that alveolar epithelial A2B adenosine receptor signaling contributes to lung protection, and they implicate inhaled A2B adenosine receptor agonists in ALI treatment.
急性肺损伤(ALI)是一种急性炎症性肺疾病,可导致危重症患者发病和死亡。然而,在许多情况下,ALI可通过有助于控制过度肺部炎症的内源性途径自发缓解。先前的研究表明,细胞外信号分子腺苷以及通过A2B腺苷受体的信号转导事件参与肺保护。在此背景下,我们推测A2B腺苷受体的组织特异性表达是先前所述的ALI减轻的原因。为了验证这一假设,我们利用两击模型,即气管内注射脂多糖(LPS)后进行损伤性机械通气,使Adora2b基因发生组织特异性缺失的小鼠暴露于ALI环境中。有趣的是,对骨髓谱系(Adora2b(loxP/loxP) LysM Cre(+))、内皮细胞(Adora2b(loxP/loxP) VE-钙黏蛋白Cre(+))或肺泡上皮细胞(Adora2b(loxP/loxP) SPC Cre(+))中Adora2b基因缺失的小鼠进行的直接比较显示,Adora2b(loxP/loxP) SPC Cre(+)小鼠的疾病易感性选择性增加。对Adora2b(loxP/loxP) SPC Cre(+)小鼠进行更详细的分析证实,其肺部炎症加剧,肺泡液体清除功能减弱。为了将A2B腺苷受体特异性激动剂直接递送至肺泡上皮细胞,我们随后使用吸入性BAY 60-6583进行了研究。事实上,雾化吸入BAY 60-6583治疗与肺水肿减轻、组织学肺损伤改善以及肺部炎症减轻有关。总的来说,这些发现表明肺泡上皮A2B腺苷受体信号传导有助于肺保护,并提示吸入性A2B腺苷受体激动剂可用于ALI治疗。