Inhibition of allergen-mediated mast cell activation by TAK1 inhibitor 5Z-7-oxozeaenol

Abstract

Introduction & Aim: Allergic inflammatory disorders are at epidemic levels worldwide. Mast cells drive this inappropriate immune response via release of a variety of pro-inflammatory mediators in response to environmental cues detected by the IgE-FcεRI complex, but we do not fully understand the contributing molecular mechanisms. Transforming growth factor β-activated kinase 1 (TAK1) is a known participant in related signaling through MAPK and NF-κB; however the role of TAK1 in IgE-FcεRI signaling and resultant allergic inflammation remains unknown. We aim to assess the role of TAK1 in IgE-mediated mast cell activation. Methods: Bone marrow-derived mast cells were sensitized with allergen-specific IgE and treated with the corresponding allergen for various times in the presence or absence of 5Z-7-oxozeaenol. Mast cell signaling was measured by western blotting, induced gene expression by qPCR, pro-inflammatory mediator release by ELISA and mast cell degranulation by β-hexosaminidase release assay. Results: TAK1-inhibition resulted in significant impairment in the phosphorylation of various MAPKs (p38, ERK and JNK) as well as NF-κB pathway kinase IκBα. Impaired gene expression of pro-inflammatory cytokines IL-4, IL-6, IL-13, and chemokines CCL1, -2, and -3 were detected. Furthermore, a drastic decrease in the concentration of pro-inflammatory cytokines, IL-6 and TNF, and chemokines CCL1 and CCL2, in stimulated cell supernatants was detected. Finally, a significant inhibition of mast cell degranulation was also observed in the TAK1-inhibited cells. Conclusion and Significance: These results suggest that TAK1 acts as a signaling node linking the MAPK and NF-κB pathways in mast cells responding to allergen and may warrant consideration in future therapeutic development.