Wnt-activated osteocyte-driven 3D-bioprinted scaffolds orchestrate bone remodeling, angiogenesis and innervation to accelerate critical bone defect repair

Abstract Effective repair of critical bone defects necessitates biomaterials that simultaneously couple bone remodeling (osteogenesis-osteoclastogenesis) with neurovascularization. However, existing multifunctional systems face bottlenecks, including co-culture instability and unpredictable release, due to their reliance on multiple cell types or growth factors. To address this, we developed a 3D-bioprinted scaffold by co-encapsulating SKL2001 (S24)-treated osteocyte osteogenic microenvironment (SOOME) and BMSCs in a gelatin methacryloyl (GelMA) hydrogel within a polycaprolactone (PCL) framework, which is referred to as the SOOME/BMSC@PCL scaffold. In a murine critical-sized calvarial defect model, the SOOME achieved 52.3% bone area fill at 8 weeks, a 5.1-fold increase over the BMSC-only control. It also significantly stimulated osteoclast recruitment, accompanied by elevated bone formation, induced abundant H-type vascularization and promoted neural infiltration. Transcriptomic analysis identified Vgf as a differentially expressed gene that partially contributed to the multifunctional integration of SOOME. This research establishes a simpler and more controllable strategy for synergistic regulation of osteogenic, osteoclastic, vascular and neural functions within a SOOME-centered material system, providing new insights into the functional selection of seed cells and opening avenues for clinical translation of bioactive bone grafts.