Figure 1

Determination of chondrocyte and cartilage degradation-related genes of PG peptide-stimulated chondrocytes in the presence of IFNγ. (A) RNA microarray analysis showing GO classification for differentially expressed genes (DEGs) in chondrocytes stimulated with IFNγ and PG peptides (N = 3). (B) Heat maps showing differential gene expression related to proteolytic enzymes, regulation of ECM production and chondrocyte and cartilage development. Each heat map represents log₂ (fold change) ratio of DEGs in IFNγ and PG peptides stimulated chondrocytes compared with the unstimulated condition. Color gradients represent level of expression of genes; green denotes upregulation of genes and red denotes downregulation of genes. (C) Bar graphs illustrating differential gene expression related to proteolytic enzymes, regulation of extracellular matrix production and chondrocyte and cartilage development in IFNγ and PG peptide-treated chondrocytes compared with IFNγ-only treated chondrocytes (N = 3). The significant level of fold change is cut off at 1.5 and -1.5 as shown in the black dot line. (D) Schematic diagram of selected DEGs function relates to ECM production, cartilage degradation and chondrocyte hypertrophy.