Down-regulation of miR-146a expression induces allergic conjunctivitis in mice by increasing TSLP level

Abstract

Pollen is the most common aeroallergen to cause conjunctivitis. In this study, we established a short ragweed (SRW)-induced mouse model of allergic conjunctivitis (AC) and aimed to explore the potential role of miR-146a and its downstream molecules in the development of ocular allergic infammation. The mouse model of challenge pollen was used for in vivo study. The culture model of primary human limbal epithelium (HLE) exposed to lipopolysaccharide (LPS) was performed for in vitro research. The numbers of eo-sinophils and total infammatory cells were examined using Giemsa staining. The expression of mRNA and miR-146a was determined by quantitative RT-PCR, and protein production was evaluated by Western blotting. In vivo of mice, pollen challenge induced conjunctiva infammatory response indicated by increased number of eosinophils and total infammatory cells. Interestingly, pollen signifcantly attenuated miR-146a expression while it enhanced expression of thymic stromal lymphopoietin (TSLP) and its downstream molecules, including TSLP receptor (TSLPR)/ OX40 ligand (OX40L) /CD11C. In vitro of HCE, downregulation efect of miR-146a expression induced by LPS was reversed by Bay treatment, an inhibitor for nuclear factor kappa B (NF-kB), and LPS-induced cell infammation is mediated by miR-146a-TSLP/TSLPR/OX40L/CD11C signaling pathway. This was further demonstrated by overexpression of miR-146a in mouse abrogated pollen-triggered conjunctiva infam-matory reaction as well as pollen-induced activity of TSLP/TSLPR/OX40L/CD11C signaling. Down-regulation of miR-146a expression induces allergic conjunctivitis in mice by increasing TSLP level.