Taitao Sun1, Jian Yu2, Liang Han3, Shuo Tian4, Bin Xu1, Xianbin Gong1, Qiang Zhao1, Yang Wang5. 1. Department of Orthopedics, Jining No.1 People's Hospital, Jining, China. 2. Department of Orthopedics, Heze Municipal Hospital, Heze, China. 3. Department of Orthopedics, Affiliated Hospital of Jining Medical University, Jining, China. 4. Shandong Polytechnic College, Jining, China. 5. Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China.
Abstract
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-1β, 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.
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 humancartilage 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-1β, 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.