Curcumin hinders PBDE-47-induced neutrophil extracellular traps release via Nrf2-associated ROS inhibition

Polybrominated diphenyl ethers (PBDE-47), a kind of lipophilic persistent organic pollutants (POPs) brominated flame retardant, has been widely used in various consumer products. However, the toxicity of PBDE-47 on human immune system has not been well elucidated. Neutrophil extracellular traps (NETs) contribute to the innate immune responses, and the release of NETs is recognized as the most important part of the extracellular killing mechanism. The aim of this study was to investigate the effect of PBDE-47 on NETs and its possible molecular mechanism, as well as the intervention effect of curcumin (Cur). In this study, the formation of PBDE-47-induced NETs was observed by fluorescence microscopy and scanning electron microscopy, and was also quantitatively detected by DNA dye SYTOX green. In addition, we used Cur and Nrf2 inhibitor ML385 to explore the role of reactive oxygen species (ROS), extracellular signal regulated kinase (ERK) and p38 signaling pathway in PBDE-47-induced reticular formation. We demonstrated that PBDE-47 could significantly induce the formation of NETs, and its molecular mechanism might be related to ROS burst. Cur reduced ROS and inhibited PBDE-47-induced NETs formation by interfering with Nrf2. In conclusion, this study revealed that Cur hindered PBDE-47-induced NETs via Nrf2-associated ROS inhibition, which enriched the cytotoxicity mechanism of PBDE-47, and provided a new clue for the development of Cur as an antagonist of PBDE-47-related immune injury.