Effect of JQ1 on TGF-β-induced myofibroblast phenotypic changes and proliferation. (a) Non-ILD control fibroblasts were serum-starved for 24 h and pretreated with 500 nM JQ1 or JQ1(-) for 2 h before stimulation with TGF-β1 (1ng/ml) for 48 h. Cells were stained for αSMA (green) and nuclear DNA (DAPI/Blue). (b) Cells were cultured in the absence (picture A) or presence (picture B) of TGF-β1 for 48 h before being treated with 500 nM JQ1(-) (picture C) or JQ1(+) (picture D) for further 48 h. (c) Control cells were cast in collagen gels and treated with TGF-β1 and 500 nM JQ1 (+ or -) for 24 h. Gels were released and allowed to contract for 4 h, and the gel area was measured using ImageJ. Data points are mean from experiments in two different cell lines performed in triplicate and expressed as fold change compared to the JQ1- control. (d) Control fibroblasts were serum-starved and pretreated with JQ1 (+ or -) at the indicated concentrations before stimulation with 3% fetal bovine serum (FBS) for 24 h. Proliferation was determined by BrdU incorporation. Data points are mean from experiments in two different cell lines performed in triplicate and expressed as fold change compared to the JQ1- control.