Vascular EC-derived factors promote DPC functions.

To explore the underlying molecular mechanism of crosstalk between endothelial cells (ECs) and dermal papilla cells (DPCs), we used RNA sequencing to investigate the transcriptional changes in the human follicle dermal papilla cells (HFDPC) culture induced by conditioned medium (CM) treatment from human umbilical vein endothelial cell (HUVEC) (EC-CM). Overall design: To prepare EC-CM, passage 4 (P4) HUVECs were cultured to 50%–60% confluency in a 100-mm cell culture dish in 10 mL of EGM-2 medium. Then, the medium was replaced with 10 mL of fresh EGM-2 medium for 24 h, and the EC-CM was harvested. After centrifugation at 3,000 rpm for 10 min to remove the cell debris, the EC-CM was filtered through a 0.22 µm filter (Millipore) and directly used for HFDPC culture (P4). The EGM-2 medium (10 mL) incubated for 24 h in a culture dish without cells was used as the control. After the culture of HFDPC in the EC-CM medium or control medium for 24 h, we used the Direct-Zol RNA miniprep kit (Zymo Research) and the Agilent 2200 TapeStation to extract total RNA and determine its quality, respectively.