BACKGROUND: Pneumonia is a common disease with high morbidity and even death. In our country, pneumonia is the leading cause of child death. Therefore, research on the pathogenesis of pneumonia can help improve the treatment of pneumonia. Long non-coding RNA (lncRNA) is an important regulator of disease development, and its regulatory mechanism is closely related to cellular processes. However, the function and regulatory network of lncRNA is not fully elucidated in pneumonia.

MATERIAL AND METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect the expression of CRNDE and miR-141 in lipopolysaccharides (LPS)-induced MRC-5 cells and pneumonia tissues. MTT (3-(4,5-dimethylthiazol-2-yl)-2 5-diphenyl-2-tetrazolium) assay was used to assess cell proliferation. Flow cytometry assay was performed to detect cell apoptosis in LPS-induced MRC-5 cells. Enzyme-linked immunosorbent assay and western blot were used to measure the levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, respectively. In addition, luciferase reporter assay and RNA immunoprecipitation (RIP) assay were applied to prove the relationship between CRNDE and miR-141.

RESULTS: In this study, we found that CRNDE expression was induced in LPS-induced MRC-5 cells and pneumonia tissues. Moreover, miR-141 expression was low in LPS-induced MRC-5 cells and was verified was a target miRNA of CRNDE by using luciferase reporter assay and RIP assay. The downregulation of CRNDE and upregulation of miR-141 promoted cell viability, inhibited cell apoptosis, as well as decreased the levels of IL-1β, IL-6, and TNF-α. Moreover, we demonstrated that si-CRNDE transfection increased cell viability and suppressed cell apoptosis and the levels of IL-1β, IL-6, and TNF-α, which were alleviated by anti-miR-141 transfection in LPS-induced MRC-5 cells.

CONCLUSIONS: In this study, we found that downregulation of CRNDE and upregulation of miR-141 inhibited cell apoptosis and inflammation response and promoted cell viability in LPS-induced MRC-5 cells. Low CRNDE expression increased cell growth and suppressed inflammation response, which was impaired by inhibition of miR-141. These results suggested that a novel therapeutic target was found in pneumonia treatment.

Keywords: Inflammation Mediators, Pneumonia, Aspiration, Adolescent, Cell Line, Child, Down-Regulation, Fibroblasts, Lipopolysaccharides, Lung