Circ_0070934 promotes MGAT3 expression and inhibits epithelial-mesenchymal transition in bronchial epithelial cells by sponging miR-199a-5p.

Background: Circular RNA (circRNA) has the potential to serve as a crucial regulator in the progression of bronchial asthma. The objective of this investigation was to elucidate the functional dynamics of the circ_0070934/miR-199a-5p/Mannoside acetylglucosaminyltransferase 3 (MGAT3) axis in the development of asthma.

Methods: Circ_0070934, miR-199a-5p and MGAT3 in peripheral venous blood of 38 asthmatic patients and 43 healthy controls were detected by qRT-PCR, and the expression of MGAT3 protein was examined by ELISA. The GSE148000 dataset was analyzed for differences in MGAT3. The BEAS-2B cells were transfected with circ_0070934 plasmid and small interfering RNA, miR-199a-5p mimics and inhibitors. The apoptosis level was detected by flow cytometry and MGAT3 was detected by qRT-PCR and Western blot. The expression of E-cadherin, N-cadherin, Vimentin was examined by Western blot. Interleukin-4 (IL-4) and IL-13 were used to co-stimulate BEAS-2B cells as an asthmatic airway epithelial cell model. BEAS-2B cells exposed to type 2 cytokines (IL-4 and IL-13) were treated with circ_0070934 plasmid, and the expression of E-cadherin, N-cadherin, and Vimentin was detected by Western blot. The binding relationships were verified using dual-luciferase reporter assay and miRNA pull-down assay.

Results: The expression of circ_0070934 and MGAT3 in peripheral venous blood of asthmatic patients was down-regulated, and the expression of miR-199a-5p was up-regulated. And the expression of MGAT3 was reduced in sputum of asthma patients. Down-regulating the expression of circ_0070934 could promote apoptosis of BEAS-2B cells and increase epithelial-mesenchymal transition (EMT), and this effect can be partially reversed by down-regulating miR-199a-5p. Circ_0070934 could inhibit the process of epithelial mesenchymal transition induced by IL-4 and IL-13 in BEAS-2B cells. In addition, miR-199a-5p could respectively bind to circ_0070934 and MGAT3.

Conclusion: The findings of this study indicate that circ_0070934 may function as a competitive endogenous RNA (ceRNA) of miR-199a-5p, thereby modulating the expression of MGAT3 and impacting the process of EMT in bronchial epithelial cells. These results contribute to the establishment of a theoretical framework for advancing the prevention and treatment strategies for asthma.