SNAI1 and chronic obstructive pulmonary disease: Using cigarette smoke extraction or cigarette smoke to construct COPD cell models and mouse models, a previous study verified the ceRNA mechanism of circ0061052 in vivo and in vitro and concluded that circ0061052 was involved in cigarette smoke-induced epithelial-mesenchymal transition and airway remodelling in COPD by regulating miR-515-5p through a FoxC1/Snail regulatory axis (Ma et al., 2020).