COL1A1 and chronic obstructive pulmonary disease: Here, stimulating smoker COPD fibroblasts with LPS for 4 h induced the gene expression of TGF-β1, COL1A1, and COL3A1 by 5.5 fold (p<0.0001), 4.9 fold (p<0.05), and 5.5 fold (p<0.01), respectively, relative to unstimulated control.