PP7 - Lycopene Inhibits House Dust Mites-Induced TLR4 Activation and Oxidative Stress in Respiratory Epithelial Cells

Abstract

House dust mites (HDM) are critical factors causing airway inflammation. HDM are known to activate respiratory epithelial cells to produce pro-inflammatory cytokine (IL-6, IL-8) and trigger toll-like receptor 4 (TLR4) activation. TLR4 mediates ROS production and cytokine expression in some cells. Lycopene is an antioxidant nutrient showing anti-inflammatory activity. In the present study, we investigated whether HDM induce activation of TLR4, production of ROS, and expression of cytokines IL-6 and IL-8 in A549 human respiratory epithelial cells. In addition, we examined the inhibitory effect of lycopene on HDM-induced cytokine expression and ROS production in A549 cells. As a result, HDM induced activation of TLR4, production of intracellular and mitochondrial ROS, and expression of IL-6 and IL-8 in A549 cells. TAK242, a TLR4 inhibitor, suppressed HDM-induced production of intracellular and mitochondrial ROS, and cytokine expression in A549 cells. Lycopene inhibited HDM-induced TLR4 activation, intracellular and mitochondrial ROS production, and cytokine expression in A549 cells. In conclusion, HDM activate TLR4, intracellular and mitochondrial oxidative stress, and inflammatory cytokine expression in respiratory epithelial cells. An antioxidant lycopene may be beneficial for preventing HDM-induced cytokine expression by suppressing TLR4 activation and ROS production in respiratory epithelial cells.