Fig. 5

IRF1 upregulates MRF expression during coculture with monocytes. A Heatmap of differentially expressed mRNAs (≥ 1.5-fold) in MSCs between cells cocultured with or without CD14+ monocytes. B Venn diagram showing the intersection between upregulated genes and predicted transcription factors. C IRF1 was one of the immune-related genes identified by GOChord analysis. D Dynamic changes in the expression of IRF1 mRNA at different time points during coculture, as measured by qRT–PCR (n = 3). E IRF1 protein levels at different time points during coculture, as detected by western blotting. Quantitative results were normalized to the result for GAPDH (n = 3). F The sequence of the IRF1-binding site and predicted IRF1-binding site in the MRF promoter are listed in the diagram. G Dual-luciferase reporter assays showed that knockdown of IRF1 inhibited the luciferase activity of the reporter containing the promoter region of MRF (n = 3). H IRF1, MRF and MCP1 mRNA levels in MSCs were measured via qRT–PCR after IRF1 knockdown with or without MRF overexpression (n = 3). I IRF1 and MCP1 protein levels in MSCs were detected by western blotting, and quantitative results were normalized to the result for GAPDH (n = 3). J MCP1 levels in MSC culture supernatants were quantified via ELISA (n = 3). K The number of migrated monocytes induced by MSCs was decreased after IRF1 knockdown, and overexpression of MRF partially restored the level of MCP1 (n = 3). L The number of migrated monocytes induced by MSC culture supernatants was decreased after IRF1 knockdown, and overexpression of MRF partially restored the level of MCP1 (n = 3). The data are presented as the mean ± SD; *P < 0.05, **P < 0.01, ***P < 0.001, ns not significant. All experiments were independently repeated three times