Fibronectin-guided immune–stromal cell crosstalk promotes angiogenesis in pulp–dentin complex regeneration

Abstract Macrophages are multifunctional immune cells that play crucial roles in immune regulation and tissue regeneration by interacting with various cell types. Although macrophage–stromal cell interactions are widely recognized as essential for tissue regeneration and homeostasis, their precise mechanisms in the pulp–dentin complex, a key functional unit for tooth maintenance, remain incompletely understood. In this study, we investigated the interactions between macrophages and dental pulp stromal cells (DPSCs) within a dental pulp microenvironment in response to dental caries infection. As caries progressed, macrophage–DPSC interactions became increasingly prominent. Whole-transcriptome analysis revealed that these interactions are mediated by fibronectin–integrin engagement, which induces a phenotypic shift in macrophages from pro-inflammatory to pro-angiogenic, mediated by the upregulation of angiogenic chemokines. Integrated analysis of a single-cell RNA sequencing dataset from human pulp tissue further confirmed that caries progression enhanced macrophage-driven angiogenic signalling in the endothelial cell population. Moreover, the altered secretome resulting from the macrophage–DPSC co-culture significantly enhanced in vitro endothelial tube formation and survival, indicating a strong angiogenic potential conducive to tissue regeneration. In a preclinical pulp revascularization model, the application of fibronectin during revascularization enhanced neovascularization, root dentin formation, apical maturation and organized pulp–dentin-like tissue formation. Collectively, these findings indicate that fibronectin is a key regulator that reprogrammes the damaged pulp environment into a pro-angiogenic and regenerative niche through coordinated immune–stromal interactions. This study provides a promising direction for the development of extracellular matrix-based therapeutic strategies in regenerative dentistry.