Silencing XIST mitigated lipopolysaccharide (LPS)-induced inflammatory injury in human lung fibroblast WI-38 cells through modulating miR-30b-5p/CCL16 axis and TLR4/NF-κB signaling pathway

Background - Emerging evidence shows that long non-coding RNA (lncRNA) has been a novel insight in various diseases, including pneumonia. Even though lncRNA X-inactive-specific transcript (XIST) is well studied, its role in pneumonia remains to be largely unrevealed. Methods - Expression of XIST, miR-NA-30b-5p (miR-30b-5p), and CC chemokine ligand 16 (CCL16) was detected using reverse transcriptase quantitative polymerase chain reaction and western blotting; their interaction was confirmed by dual-luciferase reporter assay. Apoptosis, inflammation, and toll-like receptor 4 (TLR4)/NF-kappa B signaling pathway were measured using methyl thiazolyl tetrazolium assay, flow cytometry, western blotting, and enzyme-linked immunosorbent assay. Results - Lipopolysaccharide (LPS) stimulation decreased cell viability and B cell lymphoma (Bcl)-2 expression, and increased cell apoptosis rate and expression of Bcl-2-associated X protein (Bax), cleaved-caspase-3, interleukin (IL)-6, IL-1 beta, and tumor necrosis factor alpha (TNF-alpha) in WI-38 cells. Expression of XIST and CCL16 was upregulated in the serum of patients with pneumonia and LPS-induced WI-38 cells, respectively; silencing XIST and CCL16 could suppress LPS-induced apoptosis and inflammation in WI-38 cells, and this protection was abolished by miR-30b-5p downregulation. Moreover, XIST and CCL16 could physically bind to miR-30b-5p, and XIST regulated CCL16 expression via sponging miR-30b-5p. TLR4 and phosphorylated P65 (p-P65) and p-I kappa B-alpha were highly induced by LPS treatment, and this upregulation was diminished by blocking XIST, accompanied with CCL16 downregulation and miR-30b-5p upregulation. Conclusions - Silencing XIST could alleviate LPS-induced inflammatory injury in human lung fibroblast WI-38 cells through modulating miR-30b-5p/CCL16 axis and inhibiting TLR4/NF-kappa B signaling pathway.