Fig. 6: Spatial cell communication analysis reveals signaling pathways and spatial dynamics of MPC-driven macrophage recruitment.
A Dot charts showing spatial transcriptomic (ST) analysis of interaction strengths among cell types at Days 0, 5, and 15. Each bubble’s size corresponds to the interaction strength. B Dot charts showing single-cell (SC) analysis of interaction strengths among cell types at Days 0, 5, and 10 postfracture. MPC mesenchymal progenitor cell, PPC proliferative progenitor cell, CH chondrocyte, HCH hypertrophic chondrocyte, EOB early osteoblast, OB osteoblast, Syn synovial cell, EC endothelial cell, MF1 inflammatory macrophage, MF2 tissue resident macrophage, OC osteoclast. C Spatial maps highlighting the colocalization of different cell types on Day 5. On Day 5, MPCs colocalized with macrophages. Insets provide magnified views of selected areas, illustrating the detailed spatial arrangement of these cells within the fracture site. D Distribution of tissue-resident macrophage scores calculated by the CARD package along the thickened periosteum from the fracture site, showing a decrease in the number of macrophages with increasing distance from the fracture (0–4 mm). R2 = 0.2962 indicates the strength of the trend. E Immunofluorescence images of macrophage distribution in fractured Gli1ER/Td mouse femurs on Day 5. Left panel: H&E staining. F Comparison of the macrophage density per square millimeter of the periosteum area near and distant from the fracture site. n = 3/group. The data are expressed as the means ± SDs and were analyzed by unpaired two-tailed t tests. G Bubble plot depicting the significance and probability of interactions between various cell types (MPC, OB, OC, MF2) across different days postfracture (D0, D5, D10). Each row represents a signaling pathway, and each column shows a specific cell type interaction, with color intensity indicating the communication probability and outlined bubbles marking statistically significant interactions. The signals in red are pathways involved in the MPC region, and the signals in blue are pathways involved in the OB region.
