Sulforaphene targets NLRP3 inflammasome to suppress M1 polarization of macrophages and inflammatory response in rheumatoid arthritis.

This work aimed to explore the therapeutic effect and target of sulforaphene (LF) in mice with rheumatoid arthritis (RA). Lipopolysaccharide (LPS) and IFN-γ were added to induce the M1 polarization of SMG cells, and later cells were pretreated with 5 µM and 15 µM LF. M1 cell proportion was detected by flow cytometry (FCM), inflammatory factors were measured by enzyme-linked immunosorbent assay, and protein levels were analyzed by western blotting (WB) assay. Besides, small molecule-protein docking and pull-down assays were carried out to detect the binding of LF to NLRP3. After the knockdown of NLRP3 in SMG cells, the effect of LF was further detected. The RA mouse model was induced with collagen antibody and LPS, after LF intervention, H&E staining was performed to detect the pathological changes in mouse synovial membrane, whereas safranin O-fast green staining was performed to detect cartilage injury, NLRP3 inflammasome and inflammatory factor levels in tissues. LF suppressed M1 polarization of macrophages, reduced M1 cell proportion and inflammatory factor levels, and suppressed the activation of NLRP3 inflammasome. After NLRP3 knockdown, LF did not further suppress the M1 polarization of macrophages. Pull-down assay suggested that LF bound to NLRP3. As revealed by mouse experimental results, LF inhibited bone injury in mice, decreased M1 cell infiltration and inflammatory response in tissues, and inhibited NLRP3 inflammasome expression in tissues. LF targets NLRP3 to suppress the M1 polarization of macrophages and decrease tissue inflammation in RA.