MTOR and osteoarthritis: Based on the microarray results from Fu et al. [23], a total of 710 mRNAs were differentially expressed in osteoarthritis tissues (fold change>4, P < 0.01, 144 upregulated and 566 downregulated); these genes were annotated in a KEGG pathway analysis, and the major altered cellular signaling pathways were found to be the MAPK, PI3K/AKT and mTOR pathways (Supplementary Figure 1A).