LncRNA-MIR222HG is a novel regulator of macrophage polarization in allergic rhinitis that functions by targeting the miR146a-5p/TRAF6/NF-κΒ axis

Background: Accumulating evidence indicates that non-coding RNAs(ncRNAs) regulate macrophage polarization in allergic diseases. However, the mechanisms underlying ncRNAs-mediated macrophage polarization in allergic rhinitis(AR) have not been systematically understood. Here, we identified lncRNA-MIR222HG as a key regulator of macrophage polarization and revealed its role in AR. Methods: Bioinformatic analyses were performed to identify the dysregulated RNAs related to AR and to subsequently construct a competitive endogenous RNA(ceRNA) network. We validated our bioinformatic analyses by performing qRT-PCR in our clinical samples (39 cases of AR and 40 controls) and animal models of AR (10 AR mice and 10 controls), respectively. Human lncRNA-MIR222HG and murine mir222hg were significantly downregulated in AR. Fluorescent in situ hybridization (FISH) was used to evaluate subcellular localization of MIR222HG/mir222hg. The MIR222HG/miR146a-5p/TRAF6 ceRNA axis was found to regulate macrophage polarization and, consequently, the pathogenesis of AR, potentially. Targeted associations between mir222hg and miR146a-5p, as well as between miR146a-5p and Traf6, were validated using dual-luciferase reporter gene assays. IL-4/LPS/OVA-stimulated RAW264.7 cells were transfected to modulate mir222hg and miR146a-5p expression. Flow cytometry, qRT-PCR and immunoblotting were performed to detect the expression of downstream genes and macrophage polarization in transfected RAW264.7 cells. Results: MIR222HG and murine mir222hg were significantly downregulated in AR. Subcellular localization revealed MIR222HG and mir222hg mainly expressed in the cytoplasm and could act as a ceRNA. a series of gain-of-function, loss-of-function and rescue experiments were conducted to verify the role of mir222hg as a ceRNA sponge-that adsorbed miR146a-5p, upregulated Traf6, and activated the IKK/IκB/P65 pathway, thus facilitating macrophage M1 polarization induced by LPS and attenuating IL-4/OVA-induced macrophage M2 polarization in RAW264.7 cells. Conclusions: Our study revealed that MIR222HG targets the miR146a-5p/TRAF6/NF-κΒ axis and modulates macrophage polarization in AR, suggesting that MIR222HG may be a novel biomarker or therapeutic target for AR.