Overexpression of indoleamine 2, 3-dioxygenase contributes to the repair of human airway epithelial cells inhibited by dexamethasone via affecting the MAPK/ERK signaling pathway

Indoleamine 2, 3-dioxygenase (IDO) catalyzes the degradation of trytophan, which serves a key role in immune suppression via regulating the production of several metabolites. The present study aimed to explore the effects and mechanisms of IDO in the repair of human airway epithelium suppressed by dexamethasone (DEX). Cell viability, proliferation and migration were evaluated using a Cell Counting Kit-8 (CCK-8), 5(6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) labeling, and wound-healing assay, respectively. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot analysis and ELISA were performed to assess the levels of IDO, the mitogen-activated protein kinase (MAPK)/extracellular regulated kinase (ERK) pathway-related factors and epidermal growth factor (EGF) expression, respectively. The results revealed that overexpression of IDO enhanced the cell viability, and promoted the proliferation and migration of 16HBE cells which repair was inhibited by DEX. Furthermore, it was indicated that overexpression of IDO affected the MAPK/ERK pathway. In conclusion, overexpression of IDO promoted the human airway epithelium repair inhibited by DEX through affecting MAPK/ERK pathway. The present study implied that IDO may be a potential genetic therapeutic agent and supported the utilization of IDO in asthma.