Objective To investigate the effect of circ_0114427 on apoptosis and inflammation of alveolar epithelial cells induced by lipopolysaccharide (LPS) and its mechanism.

Methods Human alveolar epithelial cells were cultured in vitro and transfected with si-circ_0114427, microRNA (miR)-330-5p mimics or co-transfected with si-circ_0114427 and anti-miR-330-5p, and the cellswere then treated with 10 mg/L LPS for 24 hours. The expression levels of circ_0114427 and miR-330-5p in the cells were detected using real-time fluorescent quantitative polymerase chain reaction (qRT-PCR). The protein levels of Cleaved-caspase3 and Cleaved-caspase9 were evaluated using western blot. Enzyme-linked immunosorbent assay (ELISA) was used to assess the expression of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Cell apoptosis was analyzed using flow cytometry. The interaction between circ_0114427 and miR-330-5p was validated using a dual luciferase reporter assay.

Results After LPS treatment of alveolar epithelial cells, the expression of circ_0114427 was upregulated, while miR-330-5p expression was downregulated in in the cells (P < 0.05). Knockdown of circ_0114427 or upregulation of miR-330-5p could inhibit LPS-induced apoptosis, Cleaved-caspase3, Cleaved-caspase9, IL-6, and TNF-α levels in alveolar epithelial cells (P < 0.05). Circ_0114427 directly interacted with and negatively regulated miR-330-5p. Downregulation of miR-330-5p reversed the inhibitory effect of circ_0114427 knockdown on LPS-induced cell apoptosis and inflammation.

Conclusion Knockdown of circ_0114427 can inhibit LPS-induced apoptosis and inflammation in alveolar epithelial cells, possibly through upregulation of miR-330-5p.