Fig. 1: Enhanced O-glycosylation in arthritis synovium displays signatures of GALA activation pathway.
From: ER O-glycosylation in synovial fibroblasts drives cartilage degradation
a Representative images of human tissue microarray (TMA) containing joint tissues from healthy subjects (Normal) and patients with osteoarthritis (OA), rheumatoid arthritis (RA) and psoriatic arthritis (PSA). (upper panel; scale bar, 50 μm), 5× magnified areas (lower panel, scale bar, 50 μm). Nuclei are stained with Hoechst in yellow and Tn glycan with Vicia Villosa lectin (VVL) with intensity color coded blue to white. b Quantification of Tn levels in individual cores. Data from 2 TMA slides comprising tissue sections from 21 OA, 18 RA, 6 PSA patients and 7 healthy subjects. Individual data points represent the raw integrated density of VVL staining of the core normalized to that of nuclear staining. Mean ± SEM is indicated. ∗, p < 0.05 (p = 0.0498; Normal vs RA), ∗∗∗, p < 0.001 (p = 0.0004; Normal vs OA), ns not significant (p = 0.2242; Normal vs PSA) (One-way ANOVA, Kruskal–Wallis test). c VVL staining in RA patient synovium on the left. Scale bar, 10 μm. Right panels show high magnification images (60×) in the region indicated by white box. GALNT2 was co-stained with ER marker Calreticulin (CRT) or Golgi marker TGN46 stained in red respectively. Nuclei stained with Hoescht. Arrows and arrowheads indicate cell with ER-localised GALNT2 and Golgi-localised GALNT2 respectively. Scale bar, 10 μm. d Hematoxylin and eosin (HE) histology images of synovial tissues sections from control (day 0) or CAIA mice at day 7, 10, and 14. S synovium, B bone, P pannus. Scale bar, 50 μm. e Clinical scores of four CAIA mice from day 0 to 14. Mean ± SD is indicated. ∗∗, p < 0.01 (p = 0.0015; day 10); ****, p < 0.0001 (day 7); ns not significant (p = 0.558; day 14) (One-way ANOVA test). f Representative immunofluorescence (IF) images of synovial tissues sections stained with VVL (blue-white) and nuclei (yellow) of CAIA mice from day 0 to 10. Scale bar, 50 μm. g Tn levels per nuclei in the synovium of CAIA mice from day 0 to day 14. Eight joint images from four mice were quantified per time point. Whisker plots display individual values from two paws per mouse sacrificed in each timepoint, boxes extend from the 25th to 75th percentiles, and error bars span max to min values. **, p < 0.01 (day 10, p = 0.002); ***, p < 0.001 (day 7, p = 0.0009); ns not significant (day 14, p = 0.6089) (One-way ANOVA test). h Images of synovial sections from Control or CAIA mice with GALNT2 (magenta), ER protein PDIA3 (cyan) and nuclei (yellow). Scale bar, 70 µm. Zoomed images 4×; S synovial membrane, B bone.
