TIPE2 Protects Bronchial Epithelial Cells From Pyroptosis and Oxidative Stress by Interacting With the E3 Ubiquitin Ligase FBW1A in Asthmatic Mice.

Dysfunction of respiratory epithelial cells is acknowledged as an important pathogenesis of asthma. Tumor necrosis factor-α induced protein 8 like-2 (TNFAIP8L2 or TIPE2) is a famous suppressor of hyperinflammation, which has been involved in regulating asthma progression, however, its role in pyroptosis and oxidative stress of bronchial epithelial cells is still unclear. 1 μg/mL LPS and 50 ng/mL IL-13 was used to induce dysfunction of human bronchial epithelial cells BEAS-2B, and TIPE2 expression was detected at different time points after incubation. Next, TIPE2 expression vector (pcDNA-TIPE2) was transfected into BEAS-2B cells to investigate its involvement in LPS/IL-13-induced pyroptosis and oxidative stress. Then, bioinformatics analysis and co-immunoprecipitation(co-IP) assay were used to verify the binding protein of TIPE2, and rescue experiments were performed to validate the molecular mechanism through which TIPE2 regulated pyroptosis and oxidative stress of BEAS-2B cells. Finally, ovalbumin (OVA) was used to establish an asthmatic animal model in Balb/c female mice, adenovirus-mediated overexpression vector of TIPE2 (Ad-TIPE2) was applied to administrate the asthmatic mice, and the effect of TIPE2 on the progression of asthma was investigated. LPS/IL-13 treatment induced cell death (PI+ cells) and TIPE2 downregulation in a time-dependent manner. LPS/IL-13 treatment promoted NLRP3-mediated pyroptosis, secretion of pro-inflammatory cytokines, and oxidative stress in BEAS-2B cells, while overexpression of TIPE2 was able to largely reverse the effect of LPS/IL-13. TIPE2 directly interacted with the E3 ubiquitin ligase β-Transducin Repeat-containing protein (FBW1A) and positively regulated its expression. Rescue experiments with recombinant ubiquitin protein (Ub) and the ubiquitination inhibitor MG132 demonstrated that F-box and WD repeat protein 1A (FBW1A)-mediated ubiquitination of NLRP3 and C1qbp is required in TIPE2 deficiency-induced pyroptosis, mitochondrial damage and oxidative stress. Overexpression of TIPE2 suppressed NLRP3-mediated pyroptosis and C1qbp-mediated oxidative stress and improved respiratory function and pulmonary tissue damage in vivo. TIPE2 protects asthmatic bronchial epithelial cells from NLRP3-induced pyroptosis and C1qbp-induced oxidative stress by interacting with the E3 ubiquitin ligase FBW1A in vitro and in vivo.