To examine the effect of EZH2 inhibition on gel contraction, we followed the procedure as described (25 (link)). SSc dermal fibroblasts were treated with GSK126 (0.5–10 µM) for 72 h before suspension in culture media at 2 × 106 cells/mL. Cells were then mixed with collagen solution from the Cell Contraction Assay kit (Cell Biolabs) and plated in a 24-well plate. Culture media was added after the collagen polymerized. After 1 d, the collagen matrix was released, and the size of the collagen gel was measured and analyzed after 5 h using ImageJ (24 (link)).