Scgb3a2, a member of the secretoglobin superfamily, is a small cytokine-like secretory protein of approximately 10 kDa. It is predominantly expressed in airway epithelial Club cells of the lungs and trachea. Scgb3a2 has anti-inflammatory, anti-fibrotic, and growth factor activities, and may influence various lung-related biological processes [3].

In gene knockout studies, Scgb3a2-null mice showed exacerbated ovalbumin-induced allergic pulmonary inflammation, suggesting its anti-inflammatory property [2]. In the house dust mite-induced allergic airway inflammation model, Scgb3a2-null mice also had increased inflammation, indicating that Scgb3a2 may modulate the CCR4-CCL17 pathway to exert anti-inflammatory effects [4]. In the bleomycin-induced pulmonary fibrosis model, Scgb3a2-null mice had more severe fibrosis, demonstrating its in vivo anti-fibrotic activity [5]. Additionally, in acrolein-induced apoptosis in mouse fibroblast cells, Scgb3a2 inhibited apoptosis through decreased p53 phosphorylation [1].

In conclusion, Scgb3a2 plays crucial anti-inflammatory and anti-fibrotic roles in the lungs. Studies using Scgb3a2-null mouse models have significantly contributed to understanding its functions in allergic airway inflammation and pulmonary fibrosis, providing potential insights for the treatment of related lung diseases.