Loss of BMPER causes endothelial inflammation involving a BMP-dependent mechanism. The BMP antagonist noggin attenuates expression of adhesion molecules in vitro reflected by ICAM-1 protein (A) and VCAM-1 protein (B) after BMPER knockdown. HUVECs were transfected with control siRNA or siBMPERII. Endothelial cell medium was changed and cells were treated with or without noggin (500 ng/mL). HUVECs transfected with control siRNA were exposed to TNFα and served as a positive control. Cells were lysed and used for Western blotting with anti–human ICAM-1 antibody (A), anti–human VCAM-1 antibody (B) or anti–human Id1 antibody (D). β-tubulin was used as loading control. (C) Noggin prevents leukocyte adhesion on endothelial cells transfected with BMPER siRNA in flow chamber experiments. Endothelial cells were transfected with siBMPERII or control siRNA and were exposed to noggin as indicated. TNFα stimulated endothelial cells served as a positive control. PMA activated PBMCs attached on the endothelial surface. (D) Noggin diminishes up-regulation of Id1 protein expression after BMPER knockdown. (E) BMP2 increased NFκB activity in NIH3T3 fibroblasts. NIH3T3 cells were transfected with the NFκB-responsive luciferase construct and exposed to recombinant BMP2 (100 ng/mL) for 24 hours. Afterward cells were lysed and NFκB activity was quantified in reporter assay and normalized to β-galactosidase activity (*P < .05 versus siBMPER; #P < .05 versus sinegative).