Myofibroblasts are more efficient in LTBP-1 ECM organization than fibroblasts. (A–C) LTBP-1 substrates were produced by using LTBP-1–EGFP-transfected HEK293 cells that were grown for 7 d (A), ECM was obtained after DOC treatment of LTBP-1–EGFP-transfected HEK293 cells that were grown for 7 d (B), and substrates coated with LTBP-1–EGFP were purified from supernatants of LTBP-1–EGFP-transfected HEK293 cells (C). The resulting ECM was used for scanning electron microscopy (SEM) and as substrates for hDfs and hDMfs. Fibroblastic cells were stained after 2-d growth for EGFP (green) and ED-A FN (red). Bars: (scanning electron microscopy images) 5 µm; (insets) 500 nm; (immunofluorescence images) 20 µm. LTBP-1–EGFP fibrils were quantified by image analysis from at least five images per three independent experiments to calculate mean values and SDs (***, P ≤ 0.005 using ANOVA followed by a post-hoc Tukey’s multiple comparison test). Insets show higher magnification views of cell-free ECM areas. a.u., arbitrary unit.