BMP9 inhibits HMVEC-d cell migration and cell growth, and induces GDF15 gene expression. (A) HMVEC-d monolayers were scratched to create a wound and incubated in low serum concentration (0.5% FBS) in the presence or absence of BMP9 (10 ng/mL) alone or together with ALK1ecd (15-fold molar excess over BMP9 concentration). At time 0, 24, and 48 hours after wounding, the cells were observed by phase-contrast microscopy and photographed. Results from 1 representative experiment of 5 are presented as the percent of wound closure at different times after wounding ± SE. (B) HMVEC-d's were treated for 24 hours and 48 hours with BMP9 (10 ng/mL) alone or together with ALK1ecd (15-fold molar excess over BMP9 concentration) in 5% FBS. The quantity of viable cells was determined using the WST-1 assay. Results from 1 representative experiment of 5 are expressed as absorbance (OD₄₅₀) ± SE. (C) HMVEC-d's were treated for 24 hours in the presence or absence of BMP9 (10 ng/mL) alone or together with ALK1ecd (15-fold molar excess over BMP9 concentration). mRNAs were then extracted and quantitative RT-PCR was performed for GDF15 and HPRT. Results are expressed as level of GDF15/level of HPRT gene expression. Data show 1 representative experiment ± SD of 3. (A-B)**P < .01.