Fig. 4

CD90⁺ FLS express the highest levels of Δ133p53β isoform. A p53β expressing cells (green, panel 1), Δ133p53αβγ expressing cells (red, panel 2), cells expressing either CD55⁺, CD68⁺ and CD90⁺ or CD138⁺ (magenta, panel 3); merged images (panel 4) showing co-localisation of p53β with Δ133p53β (yellow) and CD90⁺/Δ133p53β⁺ co-localisation (light pink); × 400 magnification, scale bar 50 μm. B Regional localisation of CD90⁺/Δ133p53β⁺ cells (light pink) adjacent to the blood vessels (BV, left panel), ELS (middle panel) and synovium and sub-lining (S, right panel); × 400 magnification, scale bar 50 μm. C The percentage of CD55⁺, CD68⁺, CD90⁺ and CD138⁺ cells, represented in A, which co-express p53β, Δ133p53 and both Δ133p53 and p53β. Each dot represents the results from each individual image field and a minimum of 100 cells. Lines represent the mean and standard deviation. Significance was determined using Kruskal–Wallis with Dunn’s multiple comparison (*p < 0.002, **p < 0.005 and ****p < 0.0001). D Δ133p53β isoform is located in CD90⁺ FLS. Images from the top and bottom rows show the cellular location of p53β (green, panel 1), Δ133p53αβγ (red, panel 2) and CD90 (magenta, panel 3). Panel 4 represents the merge of panels 1, 2 and 3, demonstrating the location of Δ133p53αβγ and p53β in CD90⁺ cells. Co-localisation of Δ133p53αβγ with p53β is yellow (yellow arrow) and represents Δ133p53β; note the large perinuclear aggregates; co-localisation of Δ133p53β (yellow) CD90 (magenta) is light pink (light pink arrow); co-localisation of Δ133p53αγ with CD90 is shown as a deeper pink. Panels 1 through 4 indicate panel position from left to right