Fig. 5

Fig. 5. TCC suppresses the expression of the type II collagen coding gene via DNMT1. (A) Different concentrations of TCC reduced type II collagen in human chondrocytes, as indicated by Sirius red staining. The experiments were performed with 3 biological replicates. An equal concentration of DMSO (0.025 %, V/V) was used as control. Similar results were obtained in human chondrocytes from 6 independent donors (3 female donors and 3 male donors). (B) Quantification of Sirius red staining in human chondrocytes exposed to different concentrations of TCC or an equal concentration of DMSO (0.025 %, V/V). Columns with the same letter indicate P > 0.05, while columns with different letters indicate P < 0.05. (C) TCC reduces COL2A1 expression in human chondrocytes. qPCR was performed with 3 biological replicates and 2 technical replicates. Similar results were obtained in human chondrocytes from 6 independent donors. An equal concentration of DMSO (0.025 %, V/V) was used as control. Columns with the same letter indicate P > 0.05, while columns with different letters indicate P < 0.05. (D) TCC reduces type II collagen in human chondrocytes. Western blotting was performed with 3 biological replicates, and similar results were obtained in human chondrocytes from 6 independent donors. GAPDH was employed as a loading control. (E) TCC stimulates DNMT1 expression in human chondrocytes. qPCR was performed with 3 biological replicates and 2 technical replicates. Similar results were obtained in human chondrocytes from 6 independent donors. Columns with the same letter indicate P > 0.05, while columns with different letters indicate P < 0.05; (F) GO enrichment of the differentially expressed genes in the zebrafish anal fin joint treated with TCC; (G) Distribution of genes within the GO term of negative regulation of gene expression according to GSEA; (H) Distribution of genes within the GO term of DNA metabolic processes according to GSEA.