ACTA2 and chronic obstructive pulmonary disease: Moreover, COPD-derived phLF displayed lower levels of Epithelial-to-mesenchymal (EMT) markers such as smooth muscle alpha (α)-2 actin (ACTA2) and Collagen 1 (COL1A1) as shown in Figure 2C. To better understand the senescence programs in the different diseases and how they change over culturing time, we characterized multiple well-accepted senescence markers in phLF from COPD, IPF, and Control lungs after short (Day 3, Figure S1) and prolonged culture (Day 7, Figure 2D).