Abstract
MKK3 is a member of the p38 MAPK signalling pathway. Studies have shown that MKK3 is an important factor in non allergic inflammatory and Th1 responses. Less is known about the role of MKK3 in allergic inflammation and allergic diseases. Proteomic analysis was performed on peripheral blood cells obtained from 22 healthy and 18 allergic asthmatic patients. Lysates from purified lymphocytes were separated by SDS-PAGE and the protein inventories of each sample were identified using mass spectrometry. A 3.65 fold increase in the expression of MKK3 was observed in CD8+ T lymphocytes from asthmatic in relation to healthy volunteers, (% vol protein abundance). Western blot (WB) analysis showed MKK3 expression in human CD4+ lymphocytes, human endothelial cells (HUVECs) and human epithelial cells (HBECs) but not in neutrophils or eosinophils. However, using densitometric analysis we found no differences between healthy and asthmatic subjects (n=10) in any of the cell types analysed. Real time PCR studies showed no expression of MKK3 isoform C in any tissue or cell type. However, large quantities of isoform B gene expression were found in neutrophils and lung tissue from patients with COPD (isoform A: 450 vs Isoform B: 1500 relative expression (ACT)). MKK3 expression was also measured in lung samples from mice treated with lipopolysacharide (LPS) or saline. Densitometric analysis of WB data showed that LPS treated mice developed an increased total MKK3 protein expression compared to saline-treated mice (sham: 49 vs LPS: 60 A.U. p≥0.05). No significant increase in expression in these tissues was observed in mice allergic to ovalbumin. In conclusion, MKK3 is differentially expressed under non-allergic and allergic conditions.
- © 2011 ERS
