(A) Expression levels of UHRF1 and DNMTs (DNMT1, DNMT3A, and DNMT3B) mRNA in synovium obtained from patients with OA (n = 32) and RA (n = 30). (B) Spearman’s correlation between UHRF1 mRNA expression in RA synovium (n = 30) and disease activity score 28-CRP (DAS28) as well as levels of C-reactive protein (CRP) and age. (C) Correlation of UHRF1 expression in RA synovium with 6-month response to DMARD treatment measured by ΔDAS28-CRP (https://peac.hpc.qmul.ac.uk/). (D) Top, Western blot analysis of OA synovium (n = 5) and RA synovium (n = 5). Bottom, quantification of relative UHRF1 protein levels. (E) H&E staining and immunofluorescence staining for UHRF1 (red); PDPN, FAP, CD45 (green); and DAPI (blue) in specimens from multiple patients with RA (P1–P4). Scale bar: 100 μm. Arrow and arrowhead indicate UHRF1+ cells in cells positive for SF markers PDPN and FAP and leukocyte marker CD45, respectively. (F) Quantification of UHRF1+ cell number in CD45+ cells and CD45– cells among total UHRF1+ cells (n = 19). (G) Spearman’s correlation between DAS28 and number of UHRF1+ cells per tissue area (n = 19). Mean ± SD is shown. *P < 0.05 and **P < 0.01 by Mann-Whitney U test in A and D, and by Wilcoxon signed-rank test in F. All data were obtained from 5–32 independent experiments.