Figure 2

Arachidonic acid metabolic pathways and the role of IL-13. The prostaglandin pathway (red), the leukotriene pathway (blue), and the lipoxin pathway (green). PGE2 has inhibitory effects on leukotriene production including inhibition of 5-LO translocation from the cytoplasm to the nucleus and abrogation of leukotriene synthesis [24]. IL-13 down-regulates PGE2 both directly and indirectly through effects on PGES and COX-2. IL-13 also induces 15-LO that is correlated with asthma severity. IL-13 induction of 15-LO stimulates formation of 15-HETE and a metabolite of this enhances MUC5AC expression in human airway epithelial cells.