Figure 1. Effects of CXCL4^47–70 and CXCL4L1^47–70 on endothelial cell proliferation.

Firstly, bovine aortic endothelial GM7373 cells were incubated with a range of mitogenic stimuli either in the presence or absence of CXCL4^47–70 or CXCL4L1^47–70 (both 0.4 μg/ml) for 24 h (A). Cell counts after incubation with one of the carboxy-terminal peptides were expressed as percentages (mean ± s.e.m.), relative to cell counts after stimulation with the indicated mitogenic stimulus alone (100%; dotted line). As only 3 independent experiments were included in this preliminary screening, no statistical significance was reached. HMVEC were stimulated with either control medium (CO), CXCL4^47–70 or CXCL4L1^47–70 (both 0.1 to 3 μg/ml), combined with 3 ng/ml EGF (B) or as single stimuli (C) over the course of 3 to 4 days. Afterwards plates were developed according to MTT assay protocol. Optical density was determined at 570 nm and 630 nm. The proliferation index in condition X (mean ± s.e.m.) represents the ratio of the calculated ΔOD570–630_X over ΔOD570–630_CO, in which control treatment serves as an internal reference (PI= 1; dotted line). A: n= 3; B and C: n= 6 to 7; *p<0.05, **p<0.01 (versus CO); $p<0.05, $$p<0.01 (versus EGF)