Fig. 6

Piericidin diglycoside S18 suppresses PTPN22-mediated osteogenic responses in vitro. Human AVICs were pretreated with S18 for 1 h followed by exposure to OM for 3 days. A-B The PTPN22 protein and mRNA levels were decreased in human AVICs treated with S18. n = 5. C Representative micrographs of the immunofluorescence staining of PTPN22 (red) expression in human AVICs treated with S18 (DAPI: blue). n = 5. Scale bar = 100 μm. Values are the means ± SEM. #p < 0.05, ##p < 0.01 vs. the control group, *p < 0.05; **p < 0.01 vs. the OM group. D-E Human AVICs were transfected with pCMV3-PTPN22 or pCMV3-control. Immunoblotting results show ALP, Runx2 and BMP2 expression in human AVICs. n = 3. Values are the means ± SEM. ##p < 0.01 vs. control group, **p < 0.01 vs. pCMV3-PTPN22 group. F-G AVICs were treated with nonspecific control or PTPN22-specific siRNA and treated with OM and S18 for the indicated times. Representative immunoblots and corresponding quantifications show that ALP, Runx2 and BMP2 expression was decreased in PTPN22 knockdown human AVICs. n = 5. Values are the means ± SEM. *p < 0.05, **p < 0.01, n.s. H-I Western blot analysis was used to detect the levels of NF-κB and ERK1/2 phosphorylation. n = 4. Values are the means ± SEM. #p < 0.05 vs. control, *p < 0.05 vs. the OM + S18 group