Fig. 5.

PA-L1/LF impairs the function of primary human endothelial cells.

(A) PA protein-dependent translocation of LF into the cytosol of HMVEC and HUVEC cells. HUVEC and HMVEC cells were incubated with either PA-L1/LF (6 nM/6 nM) or PA/LF (6 nM/6 nM) for 2 or 4 h. The binding and proteolytic processing of PA proteins, the binding and translocation of LF, and the MEKs cleavages were detected by Western blotting using the corresponding antibodies. The non-specific bands, indicated by the arrow heads left of images, served as protein loading controls in these experiments.

(B-C) Cytotoxicity of PA-L1/FP59 (B) and PA-L1/LF (C) to human primary vascular endothelial cells. HUVEC and HMVEC were treated with the indicated toxins as described in Fig. 1. The expression of MMPs by the endothelial cells was evidenced by their high sensitivity to PA-L1/FP59.

(D) PA-L1/LF can efficiently inhibit the migration of vascular endothelial cells toward angiogenic factors-containing endothelial cell growth medium (GM). The experiments were performed as described in the Materials and Methods section. SFM, serum and angiogenic factors free medium.