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

Abstract

Abstract BackgroundAccumulating 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.MethodsBioinformatic 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. ResultsMIR222HG 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. ConclusionsOur 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.