Long Non-coding RNA THRIL Mediates Cell Growth and Inflammatory Response of Fibroblast-Like Synoviocytes by Activating PI3K/AKT Signals in Rheumatoid Arthritis.

The present study explored the possible functions and the underlying mechanism of tumor necrosis factor-α (TNF-α) and heterogeneous nuclear ribonucleoprotein L (hnRNPL)-related immunoregulatory lncRNA plasmacytoma variant translocation 1 (THRIL) in rheumatoid arthritis (RA). Serum samples were collected from patients with RA. Primary fibroblast-like synoviocytes (FLSs) were separated from synovial tissues and cultured for subsequent cell experiments by transfecting different vectors. The qRT-PCR analysis was employed for evaluating the levels of THRIL in the serum. Enzyme-linked immunosorbent assay (ELISA) analysis was employed to detect the levels of inflammatory cytokines. MTT assay and Annexin V-FITC/PI apoptosis assay were used to evaluate the cell viability and apoptosis, respectively. Besides, the levels of the apoptotic proteins and the pathway-related proteins were measured by western blotting. Pearson's correlation analysis was used to assess the correlation between THRIL and clinical parameters. THRIL was overexpressed in the blood of patients with RA as compared with healthy participants (p < 0.05). The THRIL levels in the RA blood sample were positively associated with TNF-α levels, DAS 28, and ESR (p < 0.001). TNF-α treatment significantly inhibited cell viability and enhanced cell apoptosis. Furthermore, it elevated the levels of IL-1ß and MMP-3 (p < 0.05), whereas the suppression of THRIL reversed these effects in TNF-α-treated RA-FLSs (p < 0.05). Moreover, the reduced THRIL remarkably reduced the expression of p-PI3K and p-AKT (p < 0.05) in TNF-α-treated RA-FLSs. The present study revealed that THRIL could regulate cell growth and inflammatory response of FLSs by activating the PI3K/AKT signaling pathway, subsequently playing important roles in promoting the occurrence and development of RA.

Knockdown of Long Non-Coding RNA RP11-445H22.4 Alleviates LPS-Induced Injuries by Regulation of MiR-301a in Osteoarthritis.

BACKGROUND/AIMS: Several long non-coding RNAs (lncRNAs) play vital roles in osteoarthritis (OA), whereas the role of lncRNA RP11-445H22.4 in OA remains unclear. The study aimed to investigate the effect of lncRNA RP11-445H22.4 on lipopolysaccharide (LPS)-induced cell viability, apoptosis and inflammatory injury of OA. METHODS: The expression of RP11-445H22.4, miR-301a and CXCR4 in human cartilage ATDC5 cells were altered by transfection, and then cells were exposed to 5 µg/ml LPS for 12 h. Then cell viability, apoptosis, apoptosis-related factors and inflammatory cytokines were analyzed by CCK-8, flow cytometry, western blot, RT-qPCR and ELISA, respectively. Dual-luciferase reporter assay was performed to assess the binging sites of RP11-445H22.4 and miR-301a. The signal pathways of NF-κB and MAPK/ ERK were determined by western blot. RESULTS: LPS reduced cell viability, increased apoptosis and stimulated release of IL-1ß, IL-6, IL-8 and TNF-α. However, RP11-445H22.4 inhibition significantly rescued LPS-induced injuries by promoting cell viability, suppressing apoptosis and inflammatory cytokines secretions in ATDC5 cells. In addition, miR-301a directly bound to RP11-445H22.4, and suppression of miR-301a inversed the effects of RP11-445H22.4 inhibition. Furthermore, CXCR4 was a direct target of miR-301a, and CXCR4 silencing increased cell viability, decreased apoptosis and inflammatory cytokines secretions in LPS-treated ATDC5 cells. Besides, we found that CXCR4 silencing blocked LPS-activated NF-κB and MAPK/ERK pathways. CONCLUSIONS: The study indicated that lncRNA RP11-445H22.4-miR-301a-CXCR4 axis played an important role in cartilage ATDC5 cells and provided a theoretical basis of lncRNA RP11-445H22.4 in OA.