Chi3l1 induces endothelial inflammation in vitro. (A-B) HUVECs and iMAECs were treated with rhChi3l1 protein for 24 h, then (A) THP1 monocyte adhesion to ECs and (B) NO level were determined (n = 5). (C-D) HUVECs and iMAECs were transfected with Chi3l1 siRNA (siChi3l1, 150 nM) or control siRNA (siControl) for 24 h. Cells were then treated with IL-6 (10 ng/mL; 24 h), and (C) monocyte-EC adherence and (D) NO level were determined (n = 5). (E-G) HUVECs and iMAECs were transfected with siChi3l1 or siControl. After 24 h, cells were treated with IL-6 for 24 h, and the mRNA expression of (E) VCAM1, (F) ICAM1, and (G) eNOS was determined by qPCR (n = 5). All data are shown as mean ± SEM, *p < 0.05 as determined by paired t-test.