Abstract
House dust mites (HDM) can cause DNA double-strand breaks in the lungs of asthmatic patients. However, the molecular mechanisms driving DNA damage and repair in HDM-induced asthma are yet to be elucidated. Thus, in this study, HDM treatment was applied to BEAS-2B cells and mice to mimic the pathological process of asthma in vitro and in vivo, respectively. γ-H2AX foci and expression were measured by immunofluorescence staining and western blot, respectively. The levels of interleukin (IL)-4, IL-6, IL-13, and tumour necrosis factor α (TNFα) were measured using enzyme-linked immunoassay. The expression of USP25 and BARD1 was measured by reverse transcription quantitative PCR and western blot. Co-immunoprecipitation and ubiquitination assays were employed to detect the relationship between USP25 and BARD1. As per the results, it was found that the deubiquitylating enzyme USP25 repressed HDM-induced DNA damage and the production of proinflammatory cytokines, including TNF-α, IL-4, IL-8, and IL-13, in BEAS-2B cells; in contrast, the depletion of USP25 led to the opposite effects. USP25-mediated inhibition of DNA damage and inflammation was facilitated by the stabilizing protein BARD1, which is a tumor suppressor that principally functions by promoting DNA repair and replication in BEAS-2B cells. Furthermore, USP25 was found to robustly augment BARD1 protein abundance and prevent HDM-induced DNA damage and inflammation in vivo. Taken together, these results suggest a novel mechanism contributing to DNA damage and repair in HDM-induced asthma and that selectively modulating this pathway could lead to a novel therapeutic approach for controlling and managing asthma due to HDM exposure.