Long Non-coding RNA GAS5/miR-520-3p/SOCS3 Axis Regulates Inflammatory Response in Lipopolysaccharide-Induced Macrophages.

Sepsis is mainly caused by infection, and inflammation plays a vital role in the progression of sepsis. Increasing evidence shows the regulatory mechanism of long non-coding RNA growth arrest-specific 5 (GAS5) in inflammatory response. However, the potential role of GAS5 in sepsis was not really clear. Here, we set to investigate the role and mechanism of GAS5 in the inflammatory response of lipopolysaccharide (LPS)-induced macrophages in vitro. Levels of GAS5, microRNA-520-3p, suppressor of cytokine signaling 3 (SOCS3) and inflammatory cytokines tumor necrosis factor-α (TNF-α), and interleukin (IL)-6 and IL-1β were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Nitric oxide (NO) release was measured through flow cytometry. The levels of TNF-α, IL-6, and IL-1β were also detected using ELISA. Dual-luciferase reporter and RNA pull-down assays were performed to clarify the relationship between miR-520-3p and GAS5 or SOCS3. Western blot was carried out to assess SOCS3 protein expression in macrophages. GAS5 level was remarkably decreased in sepsis serum and it was inversely related to the severity of sepsis. Upregulation of GAS5 repressed inflammatory response in LPS-induced macrophages, and the inhibitory effect was returned by miR-520-3p mimics. Moreover, miR-520-3p inhibitor downregulated the levels of inflammatory factors of TNF-α, IL-6, and IL-1β, as well as suppressed NO release. Mechanically, GAS5 functioned as a sponge of miR-520-3p and miR-520-3p directly targeted SOCS3. GAS5 regulated inflammatory response by the miR-520-3p/SOCS3 axis in LPS-induced macrophages, which furnished a novel therapeutic idea in clinical treatment of inflammation-induced sepsis.