Inflammatory stimulation leads to decrease in HOXA4 protein in cultured cells. Human aortic endothelial cells (EC1 and EC2), and SMCs (SMC1 and SMC2) were stimulated with INF-γ, and macrophages (MP1 and MP2) were stimulated with LPS and INF-γ, and assayed for HOXA4 protein by Westerns blots. Results were standardized with β-actin protein (ACTB) levels. Shaded boxes represent stimulated cells. All but one of the cell lines (EC2) exhibited downregulation of HOXA4 levels within 18 hours of exposure to inflammatory stimuli. The decrease in HOXA4 levels was statistically significant (P < 0.0007).