Apart from Wnt/β-catenin signaling, noncanonical Wnt5A/B and their receptor FZD8 were upregulated or activated by TGF-β1 in pulmonary fibroblasts and lung tissues or CS from COPD patients, which impaired endogenous lung repair and induced inflammatory responses in COPD lung [46, 50, 53]. Here, TGFB1 is linked to chronic obstructive pulmonary disease.