AKT1 and rheumatoid arthritis: However, rapid downregulation of FoxO1 in rheumatoid arthritis fibroblast-like synoviocytes in response to IL-1β or PDGF stimulation is independent of Akt and results from accelerated c-Jun N-terminal kinase (JNK)-mediated degradation of FoxO1 mRNA (Grabiec et al., 2015).