Effects of TNF-α on autophagy of rheumatoid arthritis fibroblast-like synoviocytes and regulation of the NF-κB signaling pathway.

Rheumatoid arthritis (RA) is a common chronic autoimmune disease, which seriously harms human health. The hyperplastic growth of fibroblast-like synoviocytes (FLSs) plays a key role in the pathogenesis of RA. However, the pathogenesis of RA remains unclear. In this experiment, we confirmed that Tumor necrosis factor alpha (TNF-α) could activate the autophagy of RA-FLSs. 3-Methyladenine (3-MA) and Chloroquine (CQ), two types of autophagy blocker, combined with TNF-α were used to treat FLSs. The results showed that this treatment caused a reduction in the level of autophagy-related protein, significant increases in the expression of apoptosis-related protein and the apoptosis rate, and significant inhibition of the proliferation-promoting ability of TNF-α. Ammonium pyrrolidinedithiocarbamate (PDTC), a specific nuclear factor kappa-B (NF-κB) activity blocker, significantly inhibited autophagy induced by TNF-α. Collectively, these findings showed, for the first time, that TNF-α can up-regulate autophagy activity and activate the NF-κB signal pathway. Inhibition of autophagy can improve the imbalance of proliferation/apoptosis of FLSs aggravated by TNF-α to some extent, thus delaying the progression of RA. The NF-κB signal pathway may be involved in the regulation of FLSs autophagy by TNF-α.