TJP1 and chronic obstructive pulmonary disease: Airway epithelial type 2 (AT2) cells from patients with IPF and chronic obstructive pulmonary disease (COPD) had reduced expression levels of E-cadherin and zona occludens-1, whereas collagen-I and α-smooth muscle actin expression levels were increased in parallel with increased PAI-1 and reduced uPA expression levels [62, 63].