Figure 2.

Angptl2 stimulates leukocyte adhesion to the native endothelium in ATX but not WT mice. A, Expression of P‐selectin and ICAM‐1 mRNA in freshly isolated aortic ECs from WT (n=7) and LDLr^−/−; hApoB^+/+ (ATX; n=6) mice was quantified by quantitative RT‐PCR and normalized to cyclophilin A after stimulation or not with purified recombinant angptl2 (100 nmol/L). Data are mean±SEM of n mice. *P<0.05 vs control; †P<0.05 vs condition‐matched in WT mice. B, Leukocytes from n=12 WT and n=6 ATX mice were labeled with ⁵¹Cr and incubated with aortic segments stimulated or not (control) with thrombin (10 U/mL) or purified recombinant angptl2 (100 nmol/L). Adherent ⁵¹Cr‐leukocytes were counted, and results are expressed as number of adherent cells/mm² of endothelium surface area. Data are mean±SEM of n mice. *P<0.05 vs control; †P<0.05 vs condition‐matched in WT mice. C, Aortic segments from n=16 WT mice (left) and n=9 ATX mice (right) were preincubated with anti‐P‐selectin or anti‐ICAM‐1 antibodies or the corresponding isotype‐matched IgG prior to stimulation with purified recombinant angptl2 (100 nmol/L). Adhesion of ⁵¹Cr‐leukocytes was then quantified. Data are mean±SEM of n mice. *P<0.05 vs control; †P<0.05 vs +angptl2 condition; φP<0.05 vs antibody+angptl2 condition. Angptl2 indicates angiopoietin like‐2; WT, wild type; EC, endothelial cell; LDL, low‐density lipoprotein; RT‐PCR, real‐time polymerase chain reaction; IgG, immunoglobulin G; ICAM‐1, intercellular adhesion molecule‐1.