FIGURE 5.

Mitochondrial ROS are required for TGF-β-induced gene expression in lung fibroblasts obtained from patients with lung fibrosis and scleroderma. A, primary cultures of lung fibroblasts from each of four patients with lung fibrosis were treated with TGF-β (5 ng/ml), and 30 min later, intracellular H₂O₂ levels were measured using Amplex Red. Values are presented as the -fold change compared with cultures of NHLFs. B and C, primary lung fibroblasts cultured from two patients with scleroderma-associated pulmonary fibrosis were treated with TGF-β (5 ng/ml) in the presence or absence of Mito-CP or its control cation (TPP), and 24 h later, the levels of mRNAs encoding α-SMA and NOX4 were measured by quantitative RT-PCR. D and E, the experiments were repeated with lung fibroblasts from two patients with idiopathic pulmonary fibrosis. Error bars represent mean ± S.E. (n = 3 for all measures). *, p < 0.05 for comparison between fibroblasts from patients with lung fibrosis and NHLFs; †, p < 0.05 for comparison between TGF-β and the control; ‡, p < 0.05 for comparison between Mito-CP and TPP. SSc, systemic sclerosis (scleroderma); IPF, idiopathic pulmonary fibrosis.