KEGG pathway analysis of DEPs indicated a remarkable difference in motility capacity between UC-MSCs and BM-MSCs. (A) A bubble graph describing the distribution of DEPs in a classified KEGG pathway. The bubble size represents the differential protein expression level. The dark bubbles show that the protein level in UC-MSCs is higher than that in BM-MSCs, whereas the light bubbles show the opposite trend. (B) A KEGG pathway map with additional manual annotations and links. The red boxes represent the DEPs detected in the experiment. The red boxes with red oval frames existed in the original KEGG pathway, and the red boxes with no oval frames and red links were added in line with a related KEGG pathway. BM-MSC, bone marrow mesenchymal stem cell; DEP, differentially expressed protein; KEGG, Kyoto Encyclopedia of Genes and Genomes; UC-MSC, umbilical cord mesenchymal stem cell.