IL-12 Contributes to the Development of Asthma by Targeting HIF-1α/NLRP3 Pathway through Runx3

The aim of the study was to determine the role and mechanism of runt-related transcription factor 3 (Runx3) in the development of asthma.

An asthma mouse model was constructed and validated by hematoxylin-eosin analysis of lung tissue and noninvasive enhanced pause (Penh) evaluation of airway hyperresponsiveness. Then, the levels of Runx3 and interleukin (IL)-12 in peripheral blood and lung tissue were detected by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. By use Runx3+/- mice, the effect of Runx3 downregulation on ovalbumin (OVA)-induced asthma was investigated. After stimulated by different doses of IL-12, the expressions of Runx3, hypoxia inducible factor-1α (HIF-1α), and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) in BEAS-2B cells were tested through Western blot and immunofluorescence. Subsequently, BEAS-2B cells treated with 20 ng/mL IL-12 were divided into control, Runx3 overexpression negative control, Runx3 overexpression, HIF-1α inhibitor, and Runx3 overexpression + HIF-1α agonist groups. The Western blot, immunofluorescence, and ELISA indicators were tested repeatedly.

The increased number of inflammatory cells and Penh value confirmed the success of the asthma mouse model. IL-12 expression was significantly increased, and Runx3 was reduced in asthma mice compared with wild-type mice. Meanwhile, the level of immunoglobulin E (IgE) in serum, cytokines in bronchoalveolar lavage fluid, and IL-12, HIF-1α, NLRP3 in the lung were significantly elevated in Runx3+/- mice. With the increase of IL-12 concentration, Runx3 protein expression decreased, while HIF-1α and NLRP3 expression increased. Further mechanistic studies suggest that Runx3 ameliorates IL-12-induced BEAS-2B injury by inhibiting HIF-1α/NLRP3 pathway.

These results suggested that IL-12 contributes to the development of asthma by targeting HIF-1α/NLRP3 pathway through Runx3, thus providing a novel strategy for asthma therapy.