Figure 4 Protein-protein interaction (PPI) network construction and topology analysis. (A) The PPI network of compound targets and rheumatoid arthritis (RA)-related targets. (B) The Core PPI network excavated from A. (C, D) Clusters of the core PPI network excavated from B. The green, blue, red nodes in C and D represent compound targets, RA-related targets, and the overlapping targets respectively. The size of the nodes in C and D is illustrated in descending order of degree centrality (DC) with a bigger size means the node being more “central.”