Interfering Hsa_circ_0001226 Mitigates LPS-Induced Beas-2b Cell Injury by Regulating Mir-940/Tgfbr2 Pathway

Abstract

Background: Sepsis-associated acute lung injury (SA-ALI) is a serious threat to human health. A growing body of evidence suggested that circular RNAs may be involved in ALI progression. The aim of this study was to investigate the effect and mechanism of circ_0001226 on lipopolysaccharide (LPS)–induced BEAS-2B cells. Methods: BEAS-2B cells were stimulated with LPS to establish a SA-ALI cell model. The expression of circ_0001226, miR-940, and transforming growth factor beta receptor II (TGFBR2) were monitored by quantitative real-time polymerase chain reaction. Cell proliferation and apoptosis were evaluated by the Cell Counting Kit-8, 5-ethynyl-2′-deoxyuridine assay, and flow cytometry. The levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α were calculated by enzyme-linked immunosorbent assay. Western blot was implemented to test the protein levels of PCNA, Bax, and TGFBR2. Dual-luciferase reporter assay and RNA pull-down assay were adopted to investigate the interaction between circ_0001226 and miR-940, as well as TGFBR2 and miR-940. Results: The levels of circ_0001226 and TGFBR2 were elevated, and miR-940 was decreased in SA-ALI serum specimens and LPS-evoked BEAS-2B cells. Besides that, circ_0001226 interference contributed to cell proliferation and restrained apoptosis and inflammation in LPS-induced BEAS-2B cells. Mechanically, circ_0001226 worked as a molecular sponge of miR-940 to regulate TGFBR2 expression. Conclusion: Circ_0001226 deficiency weakened LPS-mediated proliferation inhibition and inflammatory processes in BEAS-2B cells by binding miR-940 and regulating TGFBR2.