U937 monocytes

The present study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki with the approval of the Institutional Medical Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University. The cell lines of U937 monocytes and HUVECs are both purchased from the American Type Culture Collection (Manassas, VA, USA). U937 monocytes are cultured in RPMI1640 medium (Invitrogen, Carlsbad, CA, USA) with 20% fetal bovine serum (Invitrogen). HUVECs are cultured with human endothelial SFM (Invitrogen) with 20% fetal bovine serum (Invitrogen), 100 μg/ml heparin (Sigma-Aldrich, St. Louis, MO, USA), and 200 μg/ml endothelial cell growth supplement (Becton, Dickinson and Company, Frankin Lakes, NJ, USA). The 3 to 5 passages are used for experiments. Both U937 monocytes and HUVECs are cultured in a 5% CO₂ incubator at 37°C and 90% humidity (Thermo Fisher Scientific, Waltham, MA, USA).

The study protocol conformed to the ethical guidelines of the 1975 Declaration of Helsinki and was approved by the Institutional Medical Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University.
The human umbilical vein endothelial cells (HUVECs) and U937 monocytes used in this study were both purchased from American Type Culture Collection (Manassas, VA, USA). HUVECs were cultured in human endothelial serum-free medium (Invitrogen, Carlsbad, CA, USA) with 20% fetal bovine serum (Invitrogen), 100 U/ml penicillin-streptomycin (Invitrogen), 100 μg/ml heparin (Sigma-Aldrich, St. Louis, MO, USA), and 150 μg/ml endothelial cell growth supplement (Becton, Dickinson and Company, Frankin Lakes, NJ, USA). U937 monocytes were cultured in RPMI1640 medium (Invitrogen), which contains 20% fetal bovine serum (Invitrogen) and 100 U/ml penicillin-streptomycin (Invitrogen). HUVECs and U937 monocytes were both cultured in an incubator (5% CO₂, 37 °C, and 90% humidity) (Thermo Fisher Scientific, Waltham, MA, USA).