UCP2 and idiopathic pulmonary fibrosis: To determine whether UCP2 contributed to the decreased levels of ATP in lung fibroblasts, we designed an siRNA sequence that was effective in knocking down UCP2 in human lung fibroblasts (Figure S2a–c); orthologous sequences efficiently knocked down UCP2 mRNA in mouse lung fibroblasts and rat lung epithelial cells (Figure S2d,e); greater efficiency of siRNA‐mediated knockdown was observed in IPF fibroblasts (with higher baseline mRNA expression) than in non‐IPF fibroblasts (with lower baseline mRNA expression) (Figure S2a).