Dopamine D1 receptor agonist alleviates acute lung injury via modulating inflammatory responses in macrophages and barrier function in airway epithelial cells

Acute lung injury (ALI) or its severe form, acute respiratory distress syndrome (ARDS) is a life-threatening illness without effective therapeutic interventions currently. Multiple lines of evidence indicated that overwhelming inflammatory responses and impaired epithelial barrier contributed to the pathogenesis of ALI/ARDS. Recently, dopamine (DA) system was identified to participate in various pulmonary diseases. Here, we discovered that dopamine D1-like receptors mainly expressed in macrophages and airway epithelial cells (AECs), which were downregulated by lipopolysaccharide (LPS) challenge in ALI mouse lung. SKF38393 (SKF) is a selective agonist for D1-like receptors and was demonstrated to inhibit excessive inflammatory responses and oxidative stress in THP-1 cell-derived macrophages and Beas-2B cells, as well as improve airway epithelial barrier dysfunction induced by LPS stimulation. Moreover, SKF administration could effectively decrease pulmonary inflammation, ameliorate tissue damage in the LPS-triggered ALI mice. The broad protective actions of SKF might be attributed to the activation of Nrf2 antioxidative system by use of the specific inhibitor, ML385. This study offers evidence of potent immunoregulatory activity of SKF in macrophages, AECs as well as ALI mouse model, which opens novel therapeutic avenues for the intervention of ALI/ARDS. [Display omitted] •Dopamine D1-like receptors distributed mainly in lung macrophages and AECs, which could be downregulated by LPS exposure.•SKF38393 could inhibit excessive inflammatory responses and oxidative stress in THP-1 derived macrophages.•SKF38393 was able to improve airway epithelial barrier dysfunction in Beas-2B cells induced by LPS.•SKF38393 was potent in preventing acute lung inflammation and alleviating tissue damage in LPS-induced ALI mouse model.•The broad protective actions of SKF38393 might be attributed to the activation of Nrf2 antioxidative system.