Targeting a novel hsa_circ_0000520/miR-556-5p/NLRP3 pathway-mediated cell pyroptosis and inflammation attenuates ovalbumin (OVA)-induced allergic rhinitis (AR) in mice models

The circRNAs–miRNAs–mRNAs competing endogenous RNA (ceRNA) networks involve in regulating the development of various inflammation-associated diseases, including allergic rhinitis (AR), and the present study aimed to identify novel AR-associated ceRNA networks. The mRNA and protein levels of the associated genes were, respectively, examined by real-time qPCR and western blot analysis. The targeting sites in miR-556-5p and NLRP3 were validated by performing dual-luciferase reporter gene system assay. ELISA was used to measure inflammatory cytokines secretion, and CCK-8 assay was conducted to determine cell proliferation. Here, we first identified a hsa_circ_0000520/miR-556-5p/NLRP3 signaling cascade triggered epithelium pyroptosis and inflammation to regulate the development of AR in cellular and mice models. Specifically, the pyroptosis-associated biomarkers (NLRP3, ASC, IL-1β and IL-18) and pro-inflammatory cytokines (OVA-specific IgE, TNF-α, IL-4 and IL-5) were upregulated in the nasal subjects collected from AR patients and ovalbumin (OVA)-induced AR mice models, compared to their normal counterparts. Next, using the ceRNA networks analysis software, we screened out a hsa_circ_0000520/miR-556-5p axis that potentially regulated NLRP3 in the human nasal epithelial cell line. Mechanistically, miR-556-5p targeted both hsa_circ_0000520 and 3′ untranslated region (3′UTR) of NLRP3, and knock-down of hsa_circ_0000520 inactivated NLRP3-mediated epithelium pyroptosis through miR-556-5p in a ceRNA-dependent manner. Furthermore, we proved that both hsa_circ_0000520 ablation and miR-556-5p overexpression suppressed NLRP3-mediated cell pyroptosis to attenuate AR in mice models. Taken together, we evidenced that targeting the hsa_circ_0000520/miR-556-5p/NLRP3 signaling pathway was a novel AQ1strategy to ameliorate AR progression; however, future clinical data are still required to validate our preliminary results.