Fig. 5

Regulation of global histone 3 lysine 27 trimethylation (H3K27me3) levels in osteoarthritis (OA) and adult articular cartilage. a Jumonji domain-containing 3 (JMJD3) was increased in damaged cartilage compared with undamaged cartilage from within the same knees of patients undergoing unicompartmental knee replacement for OA (n = 5 patients). b Inhibition of H3K27me3 demethylases by treatment of human articular chondrocyte (HACs) with GSK-J4 for 24 h caused a decrease in matrix metallopeptidase 13 (MMP13), prostaglandin-endoperoxide synthase 2 (PTGS2) and collagen type X, alpha 1 (COL10A1) expression (n = 4 patients, 4 technical replicates per condition). Dashed line shows control expression of each gene. c HACs were treated for 72 h with small interfering RNA (siRNA) against JMJD3, lysine (K)-specific demethylase 6A (UTX) and non-targeting siRNA control prior to RNA extraction and complementary DNA synthesis (n = 4 patients, n = 4 technical replicates per patient). Expression of MMP13, PTGS2 and COL10A1 was assessed by quantitative reverse transcription polymerase chain reaction. Dashed line shows expression level following treatment with non-targeting siRNA control. d Interleukin (IL)-1/oncostatin M (OSM)-induced proteoglycan loss from human articular cartilage explants was reduced in the presence of GSK-J4 (n = 5 patients, 3 technical replicates per condition). e Treatment of HACs with IL-1, IL-6 and transforming growth factor (TGF)-β increased JMJD3 expression. f Expression of PAI1, JMJD3 and MMP13 following 6-h treatment of HACs with TGF-β with or without GSK-J4 (n = 4 patients, 4 technical replicates per condition). *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. Data are presented as individual data points for biological replicates showing mean ± 95 % CI. a Paired t test, b–f Analysis of variance with Dunnett’s correction for multiple comparisons. GAG glycosaminoglycan