Is macrophage polarization important in rheumatoid arthritis?

Macrophages are myeloid immune cells which are strategically positioned throughout the body, where they engulf and degrade debris, dead cells, and foreign substances, and coordinating the inflammatory processes. Macrophages can be divided into two extreme subsets, classical activation (M1), and alternatively activation (M2). The symptoms and signs of rheumatoid arthritis (RA) would exacerbate with the increase in pro-inflammatory cytokines, whereas anti-inflammatory cytokines will alleviate the symptoms and signs of RA. This review, mainly discusses the effects of Notch, JNK and ERK signaling pathways on the regulation of macrophage polarization, and the effects of pro-inflammatory factors and/or anti-inflammatory cytokines produced by polarized macrophages in RA. Also, we will make an attempt to find out the importance of macrophage polarization in RA treatment as a drug target. •Macrophages have been in the spotlight because of their significant roles in inflammation.•M1, M2 macrophages secrete proinflammatory or antiinflammatory cytokines to produce different effects on RA.•Regulation of M1 macrophages and M2 macrophages by Notch signaling and JNK and ERK signaling pathway.•Searching for biomarkers of M1 and M2 macrophages may be a useful method for diagnosis or treatment in RA.