TABLE 1

MicroRNAs involved in different features of chronic obstructive pulmonary disease (COPD)

Feature	MicroRNA	Finding	Ref.
Smoke exposure	miR-101	↑ in bronchial epithelium from COPD patients versus controls and in 16HBE cells with CSE	[16]
	miR-144	↑ in 16HBE cells with CSE	[16]
	miR-200c	↓ in CSE-exposed human bronchial epithelial cells	[17]
	miR-7^#	↑ in CSE-exposed airway smooth muscle cells	[18]
	let-7c^#, miR-34c^# and miR-222	↓ with CS exposure in rat lungs	[19]
	miR-135b	↑ with CS exposure in mouse lungs	[20]
	miR-146a, miR-92a-2*, miR-147, miR-21 and miR-20	↑ with CS exposure in rat lungs	[21]
	miR-21	↑ with CS exposure in rat lungs and in serum of COPD patients and control smokers	[21]
	miR-181a	↓ with CS exposure in rat lungs and in serum of COPD patients and control smokers	[21]
	miR-340	↓ in induced sputum of control smokers versus control nonsmokers	[22]
	let-7c^# and miR-125b	↓ in induced sputum of COPD smokers versus control nonsmokers	[22]
	miR-210, miR-150, miR-146b-3p and miR-452	↓ in BAL macrophages of smokers versus nonsmokers	[23]
	miR-218^#, miR-128b and miR-500	↓ in bronchial airway epithelial cells from current smokers versus never-smokers	[24]
	miR-181d	↑ in bronchial airway epithelial cells from current smokers versus never-smokers	[21]
	miR-34b^#, miR-345, miR-421, miR-450b, miR-466 and miR-469	↓ with CS exposure in mouse lungs and not reversed after 1 week CS cessation	[25]
COPD	miR-20a, miR-28-3p, miR-34c-5p and miR-100	↓ in serum of COPD patients	[14]
	miR-7^#	↑ in serum of COPD patients	[14]
	miR-29b, miR-483-5p, miR-152, miR-629, miR-26b, miR-101, miR-106b, miR-532-5p and miR-133b	↓ in plasma of COPD patients	[26]
	miR-518b	↑ in in whole blood samples of COPD patients	[27]
	miR-15b^#, miR-132, miR-145, miR-212, miR-223, miR-342-5p, miR-422a, miR-423-5p, miR-425 and miR-486-3p	↑ in BAL cell fraction of COPD patients	[28]
	miR-29, miR-34a^#, miR-98, miR-146b-5p, miR-193a-5p, miR-218^#, miR-324-5p, miR-342-3p and miR-365	↓ in BAL cell fraction of COPD patients	[28]
	miR-15b^#, miR-223, miR-1274a and miR-424	↑ in lung tissue samples of COPD patients	[29]
	miR-199a-5p^#	↓ in Tregs from COPD patients	[30]
	miR-1^#	↓ in quadriceps of COPD patients	[31]
	miR-199a-5p^# and miR-34a^#	↑ in lung tissue samples of COPD patients compared with nonsmoking controls	[32]
Lung function	let-7c^#, miR-34b^#, miR-34c^#, miR-125a-5p, miR-30e-3p and miR-30a-3p	Positively correlated with FEV₁ in sputum	[22]
	miR-1^#	Positively correlated with FEV₁ in skeletal muscle cells	[31]
	miR-199a-5p^# and miR-34a^#	Negatively correlated with FEV₁	[32]
Inflammation	miR-146a	↓ in IL-1β/TNF-α-stimulated primary lung fibroblasts from smokers with COPD compared with smokers without COPD	[33]
Emphysema	miR-520e, miR-302d, miR-92a, miR-638, miR-211 and miR-150	↑ with decreased mean linear intercept (thus more emphysema) in lung tissue samples	[34]
	let-7c^#, let-7d, let-7e, let-7f, miR-181c, miR-181d, miR-30a-3p, miR-30c, miR-30e-5p and miR-30e-3p	↓ with decreased mean linear intercept (thus more emphysema) in lung tissue samples	[34]
	miR-15b^#	Localises in emphysematous areas in the lung	[29]
	miR-34c^#, miR-34b^#, miR-149, miR-133a and miR-133b	↓ in lung tissue samples of COPD patients with moderate compared with mild emphysema	[35]
Tissue repair	miR-15b^#	Localises in fibrotic areas in the lung	[29]

CSE: cigarette smoke extract; CS: cigarette smoke; BAL: bronchoalveolar lavage; Tregs: regulatory T-cells; FEV₁: forced expiratory volume in 1 s; IL: interleukin; TNF: tumour necrosis factor. ^#: microRNAs that have more than one association with different traits of COPD.