Table 1 Alterations in epithelial–mesenchymal transitions biomarkers in COPD and pathological significance

Snail1

EMT transcriptional activator

Higher expression in smokers, COPD with current smoking, and COPD with α1-antitrypsin deficiency, and is associated with EMT activity and lung function

[17, 71]

Twist

EMT transcriptional activator

Upregulation and nuclear transport in smokers and current-smoking COPD, and expression is closely related to both emt activity and airway obstruction

[17, 69]

S100a4

Mesenchymal marker

Upregulation in COPD and inversely associated with airflow limitation

[67, 69, 81, 82]

Zo-1

Tight junction marker

Deceased in the smokers and patients with COPD

[68, 74]

E-cadherin

Epithelial marker

The lower expression was found in smokers and patients with COPD

[68, 74,75,76,77,78]

N-cadherin

Cell-surface proteins

Increased in smokers and COPD

[75, 78]

Collagen type I

ECM proteins

Higher expression in smokers and COPD

[68, 75]

Vimentin

Mesenchymal markers

Increased in smokers and COPD, epithelial expression of vimentin correlated with airway obstruction

[67, 68, 74, 75, 77, 78]

Α-SMA

Cytoskeletal marker

Increased in smokers and COPD

[68, 74, 75, 78]

Fibronectin

ECM proteins

Increased in smokers and COPD

[75]

Mmp9

Basement membrane

Increased in smokers and COPD

[75]

Β2-microglobulin

MHC I light chain

Increased in COPD

[88, 89]

Sphingosine-1-phosphate

Bioactive sphingolipid metabolite

Upregulated and inversely associated with lung function in COPD

[81]

Cullin4A

E3 ubiquitin ligase

Upregulation in smokers and COPD, and negatively correlated with the FEV1%

[97]