ETS variant transcription factor 6 enhances oxidized low-density lipoprotein-induced inflammatory response in atherosclerotic macrophages via activating NF-kappa B signaling

Objectives: Macrophages play a critical role in atherosclerosis by contributing to plaque development, local inflammation, and thrombosis. Elucidation of the molecular cascades in atherosclerotic macrophages is important for preventing and treating atherosclerosis. This study aims to deepen the understanding of the mechanisms that regulate the function of aorta macrophage in atherosclerosis. Methods: In the current study, the expression and function of ETS variant transcription factor 6 (ETV6) in aorta macrophages in a mouse atherosclerosis model. Aorta macrophages were enriched by flow cytometry. ETV6 expression was analyzed by quantitative RT-PCR. The role of ETV6 in macrophage-mediated pro-inflammatory response was evaluated both in vitro and in vivo after ETV6 silencing. Results: A remarkable elevation of ETV6 in aorta macrophages of atherosclerotic mice was observed. In addition, in vitro analysis indicated that oxidized low-density lipoprotein (oxLDL) up-regulated ETV6 in macrophages via the NF-kappa B pathway. ETV6 silencing suppressed oxLDL-induced expression of IL-1 beta, IL-6, and TNF-alpha in macrophages in vitro. However, ETV6 silencing did not impact the uptake of either oxLDL or cholesterol by macrophages. Furthermore, ETV6 silencing suppressed oxLDL-induced activation of the NF-kappa B pathway in macrophages, as evidenced by less phosphorylation of IKK beta and NF-kappa B p65, more cytoplasmic I kappa B alpha, and lower nuclear NF-kappa B p65. Moreover, ETV6 silencing inhibited the production of IL-1 beta and TNF-alpha in aorta macrophages in vivo. Conclusion: ETV6 supports macrophage-mediated inflammation in atherosclerotic aortas. This is a novel mechanism regulating the pro-inflammatory activity of atherosclerotic macrophages.