FIGURE 1.

NETs were released from differentiated HL-60 in response to phorbol 12-myristate 13-acetate (PMA) or nicotine stimulation. (A) Human HL-60 cells were differentiated into neutrophil-like cells by treating HL-60 cells with ATRA (200 µM) for 72 h (B) NETs were induced by PMA (50 µM) or nicotine (10 µM) administration to differentiated HL-60 cells. Upper panels: Representative confocal immunofluorescence images of differentiated HL-60 cells with or without PMA or nicotine administration stained for myeloperoxidase (MPO, red), citrullinated histone 3 (Cit-H3, green), and DNA (DAPI, blue). Lower panels: Representative scanned electron microscopic images of the differentiated HL-60 cells with or without the PMA or nicotine administration. (C) Left panel: Representative immunoblot images of neutrophil elastase, citrullinated Histone H₃, and β-actin. Right panels: Densitometric analysis of immunoblots. *p < 0.05 vs. 0-h, n = 3 in each group. All data are expressed as mean ± SEM.