ß-catenin mediates the inflammatory cytokine expression induced by the Der p 1 house dust mite allergen.

The modulations of ß-catenin were analyzed during the inflammatory response induced by the Der p 1 house dust mite allergen. Der p 1 induced the dose-dependent expression of inflammatory cytokines, including interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in THP-1 human monocytic cells. The mRNA expression levels of ß-catenin were not altered, however protein levels increased following Der p 1 treatment, demonstrating that ß-catenin was modulated by post-transcriptional processes. It was also revealed that nuclear ß-catenin levels were significantly increased while cytoplasmic ß-catenin levels were reduced, which demonstrated the nuclear translocation of ß-catenin by the Der p 1 allergen. Glycogen synthase kinase 3ß (GSK3ß), a regulator of ß-catenin stability, was demonstrated to be phosphorylated following Der p 1 treatment. When ß-catenin was knocked down by the transfection of its small interfering RNA (siRNA), inflammatory cytokine expression as well as nuclear factor-κB (NF-κB) activity, which were induced by Der p 1 treatment, were all significantly reduced. The results demonstrated that Der p 1-induced inflammatory responses were mediated by ß-catenin.