MPs released by LPS-treated THP-1 cells stimulate intracellular signaling in HUVECs. A total of 100 μg/mL of MPs from LPS-treated (A) or untreated (B) THP-1 cells was incubated in serum-free conditions with HUVECs. Phosphorylation of ERK1/2 and degradation of IκB-α were observed by Western blot at the indicated times. (C) Indicated amounts of MPs from LPS-treated THP-1 cells or 10 ng/mL of TNF-α were incubated in serum-free conditions with HUVECs for the indicated time. Phosphorylation of p65 was detected by Western blot. (D) Subcellular localization of p65 was examined in HUVECs after 1 or 2 hours of stimulation with MPs from untreated or LPS-treated THP-1 cells or 10 ng/mL of TNF-α. HDAC2 served as the nuclear loading control, and GAPDH served as a cytoplasmic loading control. Results are representative of 2 independent experiments.