Down-regulation of GAS5 has diagnostic value for tuberculosis and regulates the inflammatory response in mycobacterium tuberculosis infected THP-1 cells

Objective: This study aimed to investigate the expression of long non-coding RNA (lncRNA) growth arrest-special transcript 5 (GAS5) in the serum of tuberculosis (TB) patients and discuss the mechanism of GAS5 in TB by establishing an in-vitro TB cell model. Methods: Serum expressions of GAS5 and miR-18a-5p were determined by quantitative real-time PCR (qRT-PCR). The effects of GAS5 on macrophage cell viability and the inflammatory response after MTB infection were assessed by CCK-8 and ELISA. Luciferase reporter gene assay was applied to delve into the potential target gene of GAS5. Results: The expression of GAS5 in TB patients was down-regulated, while miR-18a-5p was up-regulated, and the serum inflammatory factors were negatively correlated with the expression level of GAS5. MTB infection induced significant upregulation on the cell viability and inflammatory response but the acceleration effect could be rescued by GAS5-overexpression. Meanwhile, miR-18a-5p was recognized as the target gene of GAS5. Conclusion: This study indicated that the expression level of GAS5 in the serum of TB patients was decreased, while in the cells infected with MTB, the down-regulated GAS5 might develop a role in facilitating the cell vitality and the inflammatory response by adsorbing miR-18a-5p in the form of molecular sponge.