Circ_0038467 regulates lipopolysaccharide-induced inflammatory injury in human bronchial epithelial cells through sponging miR-338-3p

Abstract

Background: Pneumonia is a common acute lower respiratory infection in children and elders. Circular RNAs (circRNAs) have recently been uncovered to play important roles in pneumonia. However, the function and mechanism of circ_0038467 in pneumonia remain elusive. Methods: Cell viability and apoptosis were determined using the Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. The levels of interleukin 6 (IL-6), IL-8 and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA). Western blot analysis was performed to assess the expression of related proteins. Circ_0038467 was characterized by Ribonuclease R (RNase) digestion and subcellular localization assays. The levels of circ_0038467 and miR-338-3p were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The direct interaction between circ_0038467 and miR-338-3p was validated by the dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Results: Our data indicated that lipopolysaccharide (LPS) induced an inflammatory injury in 16HBE cells by repressing cell viability and enhancing cell apoptosis and proinflammatory cytokines production. Circ_0038467 was upregulated and miR-338-3p was downregulated in LPS-treated 16HBE cells. Circ_0038467 knockdown or miR-338-3p overexpression attenuated LPS-induced 16HBE cell inflammatory injury. Moreover, circ_0038467 acted as a sponge of miR-338-3p in 16HBE cells. MiR-338-3p mediated the alleviated effect of circ_0038467 knockdown on LPS-induced 16HBE cell inflammatory injury. Additionally, the Janus kinase/ signal transducer and activator of transcription 3 (JAK/STAT3) signaling pathway was involved in the circ_0038467/miR-338-3p axis-mediated regulation in LPS-induced 16HBE cell inflammatory injury. Conclusions: The current work had led to the identification of circ_0038467 knockdown that alleviated LPS-induced inflammatory injury in 16HBE cells at least partly through sponging miR-338-3p and regulating JAK/STAT3 pathway, highlighting novel molecular targets for the treatment of pneumonia.