Gasoline exhaust particles induce MMP1 expression via Nox4-derived ROS-ATF3-linked pathway in human umbilical vein endothelial cells.

Gasoline exhaust particles (GEP) are risk factors for cardiovascular disease. Activating transcription factor 3 (ATF3) is a transcription factor known to form a heterodimer with AP-1 transcription factors for its target gene expression. However, the involvement of ATF3 in GEP-induced gene expression in human umbilical vein endothelial cells (HUVECs) has not been investigated. In this study, we found that GEP, at IC₅₀ value of 59 μg/ml, induced the expression of ATF3, which led to the expression of matrix metalloproteinase 1 (MMP1) in HUVECs. GEP induce an interaction between c-Jun and ATF3, and c-Jun depletion attenuates GEP-induced MMP1 expression. Depletion of NADPH oxidase 4 (Nox4) suppressed GEP-induced reactive oxygen species (ROS) generation and the subsequent upregulation of ATF3 and MMP1, suggesting that Nox4-derived ROS play a role as upstream regulators of GEP-induced ATF3 expression and MMP1 upregulation. Furthermore, Nox4 depletion attenuated the interaction between ATF3 and c-Jun and their binding to the AP-1 binding site of the MMP1 promoter. Taken together, these findings demonstrate that GEP induce the expression of MMP1 by generating Nox4-dependent ROS, which subsequently increase ATF3 expression and its interaction with c-Jun. This leads to their binding to the promoter region of MMP1 and its transcription. These findings suggest that Nox4-derived ROS and ATF3 are critical for GEP-induced MMP1 expression.