Fig. 3

CircPTPN22 acts as a ceRNA for miR-4689. A CircPTPN22-miRNA‒mRNA interaction network constructed with Cytoscape software. B Relative expression of miR-4689 in PBMCs of 44 HCs and 45 patients with SLE. C Correlation analysis of circPTPN22 and miR-4689 expression levels. D Locations of circPTPN22 (red) and miR-4689 (green) were indicated by FISH in Jurkat T cells. The circPTPN22 probe was labelled with Cy-3, and the miR-4689 probe was labelled with FAM. Scale = 25 μm. E Real-time PCR assay for the expression of miR-4689 in Jurkat T cells transfected with LV-circPTPN22 or sh-circPTPN22. F RIP assay was performed in Jurkat T cells using anti-IgG or anti-AGO2 antibodies. The relative expression levels of circPTPN22 in immunoprecipitation were detected using real-time PCR, and the immunoprecipitated AGO2 protein was detected using western blot assay. G Prediction of the circPTPN22 binding sequence with miR-4689 and construction of the circPTPN22 MUT sequence. A luciferase reporter assay validated the binding relationship between circPTPN22 and miR-4689 in HEK-293 T cells. HCs healthy controls, SLE systemic lupus erythematosus, WT wild type, MUT mutant type. The experiments were repeated three times. **P < 0.01, ***P < 0.001; ns not significant