Figure 4. Extracellular HSP70 enhances BMP-4 activity and endothelial activation.
(A) BAEC were co-transfected with the BRE-luc luciferase reporter gene and increasing amounts of N-FLAG-MPG, -MGP-P64G or –MGP-4GlaG construct, and treated with BMP-4 (40 ng/ml) with or without HSP70 (1 or 10 ng/ml). BMP-4 activity was determined by luciferase assays.
(B) BAEC were transfected with the BRE-luc reporter gene and the N-FLAG-MPG, -MGP-P64G, –MGP-4GlaG construct or empty vector, and treated with increasing levels of HSP70 with or without BMP-4 (40 ng/ml). BMP-activity was determined by luciferase assays.
(C) BAEC were transfected with the N-FLAG-MPG, -MGP-P64G or –MGP-4GlaG construct or empty vector, and treated with BMP-4 and/or HSP70 as indicated. Cell proliferation was determined by 3H-thymidine incorporation (C) and tube formation was determined on Matrigel™ (online supplement, Suppl. Fig. II).