Blocking HOTAIR protects human chondrocytes against IL-1β-induced cell apoptosis, ECM degradation, inflammatory response and oxidative stress via regulating miR-222-3p/ADAM10 axis

Background: Long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) contributes to cartilage damages including osteoarthritis (OA). While, its role and mechanism in chondrocytes is incompletely clear. Methods: HOTAIR, microRNA (miR)-222-3p and ADAM metalloproteinase-like domain 10 (ADAM10) expressions were detected by real-time quantitative PCR and western blotting. The interaction between miR-222-3p and HOTAIR or ADAM10 was confirmed by dual-luciferase reporter assay. Cell injury was measured by MTS method, flow cytometry, western blotting, enzyme-linked immunosorbent assay for collagen Type II, type X, sex determining region Y-box 9 (SOX9), matrix metalloproteinase (MMP)-13, interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha, and special assay kits for malondialdehyde (MDA), reactive oxygen species (ROS) and superoxide dismutase (SOD). Results: HOTAIR was highly expressed in human OA cartilages and IL-1 beta-induced OA model in immortalized chondrocytes (C-28/I2). Under IL-1 beta stress, blocking HOTAIR was responsible to high mitochondrial activity and low early apoptosis rate, accompanied with increased B cell lymphoma (Bcl)-2 and LC3B-II/I proteins, boosted IL-10 and SOD productions, suppressed cleaved caspase-3 and p62 proteins, and decreased MDA and ROS levels, as well as elevated secretions of Type II collagen, Type X collagen, SOX9, MMP-13, IL-6, and TNF-alpha. Moreover, miR-222-3p was a target of HOTAIR, and its overexpression and knockdown could suppress and aggravate IL-1 beta induced chondrocytes injury. Furthermore, restoring ADAM10, a target gene of miR-222-3p, counteracted the protective role of miR-222-3p upregulation. Conclusion: HOTAIR might contribute to IL-1 beta-induced chondrocytes death, inflammation, extracellular matrix degradation, and oxidative stress in OA via miR-222-3p/ADAM10 axis.