4cRNA NEAT1 Sponge Adsorption of miR-378 Modulates Activity of Lipopolysaccharide-treated Articular Chondrocytes and Influences the Pathological Development of Osteoarthritis

Osteoarthritis (OA) is a chronic joint disease that can eventually lead to degeneration, fibrosis, fractures, and defects of the articular cartilage. Long non-coding RNA (lncRNA) is a key substance in many processes, such as epigenetic regulation and cell-cycle and cell-differentiation modulation, and its relationship with OA has been repeatedly verified.The study intended to clarify the influence of lncRNA nuclear enriched abundant transcript 1 (NEAT1), lncRNA NEAT1, on lipopolysaccharide (LPS)-induced OA chondrocytes through sponge adsorption of microRNA-378 (miR-378) and to provide novel insights into future diagnosis and treatment of OA.The research team performed an animal study.The study took place in the Department of Rehabilitation Medicine at Linyi People's Hospital in Linyi, Shangdong, China.The study's animals were 10 Sprague Dawley (SD) rats, 3-5 days old and 10-15 g in weight, of the specific-pathogen-free (SPF) grade.The rat chondrocytes for the positive control group (the model group) were treated with 500 ng/mL of LPS to induce OA. Chondrocytes treated with the same amount of normal saline were used as the negative control group. The chondrocytes of the LPS-induced rats were into six groups: (1) a positive control group transfected with NEAT1-interfering RNA, the sh-NEAT1 group; (2) a negative control group not transfected with NEAT1-interfering RNA, the NEAT1 empty vector (NC-NEAT1) group; (3) an intervention group co-transfected with NEAT1 interfering RNA and the miR-378 inhibitor sequence (Inh-miR-378 the sh-NEAT1+ Inh-miR-378 group; (4) a negative control group transfected with NEAT1 interfering RNA but not transfected with the miR-378 inhibitor sequence, the sh-NEAT1+ miR-378 negative control (NC-miR-378) group; (5) a negative control group transfected with the miR-378 inhibitor sequence but not transfected with NEAT1 interfering RNA, the NEAT1 empty vector (NC-NEAT1) + Inh-miR-378 group; (6) a negative control group not transfected with either NEAT1 interfering RNA or the miR-378 inhibitor sequence, the NC-NEAT1 + NC-miR-378 group.An OA-chondrocyte model was induced by LPS and measurements of NEAT1 and miR-378 expression were made by real-time quantitative reverse transcription (qRT)- polymerase chain reaction (PCR). Then, small NEAT1-interfering RNA (sh-NEAT1), empty vector NEAT1 (NC-NEAT1), inhibitor-sequence-miR-378 (Inh-miR-378), and negative-control-miR-378 (NC-miR-378) were transfected into cells, and cell viability and apoptosis rate were measured. Finally, the study verified the relationship between NEAT1 and miR-378.Compared to the control group, NEAT1 was significantly elevated in the model group, and its miR-378 was significantly decreased. Silencing NEAT1 can enhance OA-chondrocyte activity and decrease apoptosis. When NEAT1 and miR-378 were inhibited together, as shown fort the NC-NEAT1 + NC-miR-378 group, NEAT1 expression, as well as the multiplication and apoptosis ability of the OA-model cells, were the same as those of cells transfected with an empty vector, the NC-NEAT1 group. Also, the NEAT1 + NC-miR-378 group's cell activity was lower than that of the sh-NEAT1+NC-miR-378 group but higher than that of the NC-NEAT1 + Inh-miR-378 group. Finally, higher fluorescence activity occurred for NEAT1-mutant type (MUT) transfected with Inh-miR-378.NEAT1, which is highly expressed in OA, mediates LPS-induced OA-chondrocyte activity through sponge adsorption of miR-378.