SIRT1 and rheumatoid arthritis: Given SIRT1/AMPKα signaling has an important role in regulating macrophage polarization to an anti-inflammatory M2 phenotype, and that activation of this signaling may attenuate joint inflammation in RA, we sought to establish whether SIRT1 induces AMPKα phosphorylation and subsequent NF-κB downregulation, leading to the upregulations of M2-associated cytokines and to the downregulations of the expressions of M1-associated pro-inflammatory mediators in macrophages obtained from RA patients or SIRT1-overexpressing mice.