Inhibition of 11β-hydroxysteroid dehydrogenase 1 alleviates pulmonary fibrosis through inhibition of endothelial-to-mesenchymal transition and M2 macrophage polarization by upregulating heme oxygenase-1.

The intracellular enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) catalyzes the interconversion of active glucocorticoid (cortisol) and its intrinsically inert form (cortisone) in metabolic tissues. Although 11βHSD1 is considered a promising therapeutic target in metabolic disorders such as type 2 diabetes, obesity, and nonalcoholic steatohepatitis because of its hepatic functions, its roles in other tissues have received less attention. In this study, we show that the 11βHSD1-specific inhibitor J2H-1702 facilitates the reversion of endothelial-to-mesenchymal transition in multicellular lung spheroid models encapsulating the complex crosstalk among lung cancer cells, vascular endothelial cells, and macrophages. In vascular endothelial cells, J2H-1702 not only suppressed interleukin-1α (IL-1α) expression but also attenuated reactive oxygen species-induced DNA damage by upregulating heme oxygenase-1. Additionally, in macrophages, which are key regulators of fibrogenesis, inhibition of 11βHSD1 markedly reduced IL-1β expression, thereby modulating the pro-inflammatory phenotype of activated macrophages. In mouse models of pulmonary fibrosis, including a bleomycin-induced idiopathic model and a radiation-induced model, J2H-1702 alleviated pulmonary fibrosis and markedly improved the efficacy of nintedanib. Collectively, our data suggest that J2H-1702 holds promise as a clinical candidate for the treatment of pulmonary fibrosis associated with reactive oxygen species-induced DNA damage, endothelial-to-mesenchymal transition, and inflammatory responses.