In parallel, Milara and colleagues found increased α-smooth muscle actin (α-SMA), vimentin, collagen type I, and decreased zonula occludens (ZO)-1 expression, both in small airways sections and in primary ALI-HBEC derived from smokers and COPD patients, as compared with non-smokers (Milara et al., 2013). Here, TJP1 is linked to chronic obstructive pulmonary disease.