Fig 2: Nuclear factor erythroid‐2‐related factor 2 signalling pathway as the target for OI in a mouse arthritis model. The distal femurs of mice are sectioned with the degree of cartilage injury detected by HE staining (A) and Safranin‐O‐fast green staining (B) and the thickness of cartilage measured (C). Comparisons in OARSI cartilage damage are scored based on the degree of cartilage injury (D). The serum of mice is extracted with the content of IL‐6 in serum detected by ELISA (E). Each experiment is repeated three times. Data are presented as mean ± standard deviation (n = 3). Symbols ‘*’ indicate the significant difference set at p < 0.05 in comparison with negative control (‘NC’) under LPS induction. Symbols ‘ns’ indicate the insignificant difference set at p > 0.05 in comparison with negative control (‘NC’) under LPS induction. Symbols ‘#’ indicate the significant difference set at p < 0.05 in comparison with negative control (‘NC’) under LPS and OI exposure

Fig 3: 4‐octyl itaconate inhibits the inflammatory reaction in mouse ATDC5 cells and human C28I2 cells. The ATDC5 cells and C28I2 cells are induced with LPS (10 μg/ml) for 12 h and then treated with OI (100 μm) for 12 h. The protein levels of Il‐6, MCP‐1, Il‐10 and Tnf‐α are detected by ELISA (A–D, H, and I). The mRNA in cells is detected by qPCR (E, F, J and K). The NF‐κB p65 transcriptional activity in nucleus is detected by the NF‐κB p65 Transcription Factor Assay Kit (G and L). Each experiment is repeated three times. Data are presented as mean ± standard deviation (n = 3). Symbols ‘*’and ‘#’ indicate the significant difference set at p < 0.05 in comparison with control (‘Ctrl’) and LPS induction respectively

Fig 4: 4‐octyl itaconate inhibits the inflammatory injury in C57BL6 mice. The distal femurs of mice are sectioned with the degree of cartilage injury detected by HE staining (A) and Safranin‐O‐fast green staining (B) and the thickness of cartilage measured (C). Comparisons in OARSI cartilage damage are scored based on the degree of cartilage injury (D). The serum of mice is extracted with the content of IL‐6 in serum detected by ELISA (E). Each experiment is repeated three times. Data are presented as mean ± standard deviation (n = 3). Symbols ‘*’and ‘#’ indicate the significant difference set at p < 0.05 in comparison with control (‘Ctrl’) and LPS induction respectively

Fig 5: Changes to UGDH expression in spheroids alters cells and cytokines of the tumor microenvironment in vitro. In (A) and (B), spheroids were generated, and knockdown induced with DOX before co-culture with LP3 mesothelial adherent monolayers for 24 h and gene expression of co-cultures was measured by qRT-PCR. A Heatmap of expression of genes altered in OV90 control spheroids (shneg) compared to OV90 spheroids with UGDH knocked down (sh459), and in co-culture with LP3 cells, relative to LP3 cells alone. B Heatmap of expression of genes altered in ACI23 control spheroids (VC) compared to ACI23 spheroids with UGDH overexpression (OverX), and in co-culture with LP3 cells, relative to LP3 cells alone. Total collagen content of fibroblasts was measured after 3 days culture in conditioned medium from: C OV90 control cells (shneg) or OV90 cells with UGDH knocked down (sh459. sh939) compared to OV90 culture medium (M), D ACI23 cells with UGDH overexpression (OverX) or vector control (VC) compared to ACI23 culture medium (M). Expression of (E) IL-6 (F) IL-8 in supernatant from OV90 adherent cells or spheroids with UGDH knockdown (sh459, sh939) compared to controls (shneg). Expression of (G) IL-6 (H) IL-8 (I) CCL2 in supernatant from ACI23 adherent cells or spheroids with UGDH overexpression (OverX) compared to controls (VC). N.D not detected, *p < 0.05, **p < 0.01, ***p < 0.001