TGFB1 and chronic obstructive pulmonary disease: In the present study, we used small RNA sequencing analysis; (1) to identify TGF-β-regulated miRNAs in clinically well-characterized severe COPD and control fibroblasts, (2) to identify which miRNAs are differentially regulated by TGF-β between COPD and control fibroblasts and (3) to determine miRNAs differentially expressed between COPD and control fibroblasts.