Fig. 1

Screening system construction and drug screening. A and B Relative mRNA expression (normalized by Day 0) of Alp (A) and Ocn (B) in MC3T3-E1 cells directly cultured and co-cultured with C4-2B cells in PM (promineralization medium). C Normalized luciferase activity (Luc/GF) at 48 h in MC3T3-E1 co-cultured with C4-2B cells at indicated ratios. D Schematic of the reporter gene system and screening strategy. E Three-dimensional scatter diagram of candidate compounds in accordance with relative green fluorescence intensity (RGI), relative red fluorescence intensity (RRI) and relative luciferin luminescence intensity (RLI) for each compound. The larger dot indicates the smaller P-value. F Volcano plots show compounds that have suppressive effects on RLI (orange dots) and RRI (red dots), as well as compounds that have no effect on RGI (green dots). G Overlap between the RLI inhibiting group, RGI non-effecting group and RRI inhibiting group. H Relative luciferin luminescence intensity in ME3T3-ORE co-cultured with C4-2B cells treated with indicated compounds (2 μM, 48 h). I Fold change of Alp mRNA at different time points compared with Day 0 in ME3T3-E1 co-cultured with C4-2B cells and treated with DMSO or indicated compounds (2 μM). *P < 0.05, **P < 0.01, ***P < 0.001, ns, no significance