Preliminary study on the effect of compressive stress on the angiogenic ability of dental pulp cells

Stem cell-based dental pulp regeneration is a promising treatment for pulp necrosis, wherein vascularization is critical. Dental pulp cells (DPCs) are mechanosensitive; however, the mechanism by which compressive stress regulates their angiogenic activity remains unclear. This study investigated the underlying mechanotransductive mechanisms and optimal loading parameters.

An in vitro compressive stress model for DPCs was established. Cell proliferation and migration under varying stress magnitudes and durations were evaluated using Cell Counting Kit-8 (CCK-8) and scratch wound assays, respectively. Expression of mechanotransduction and angiogenesis targets was analyzed via quantitative reverse transcription PCR (RT-qPCR), Western blotting, and immunofluorescence. Vascularization was assessed through tube formation assays.

Optimal compression (2 g/cm²) did not impair DPC proliferation or migration. Crucially, immunofluorescence and RT-qPCR revealed this mechanical stimulus significantly activated the mechanosensor PIEZO1 and downstream YAP/TAZ signaling (PIEZO1, YAP1, WWTR1, and CTGF). Driven by this axis, mRNA expression of pro-angiogenic factors VEGFA, ANGPT2, PECAM1, CXCL12, and FGF2 was significantly up-regulated. Concurrently, protein expression of vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang-2), and platelet endothelial cell adhesion molecule-1 (CD31) increased, ultimately enhancing DPC capillary-like network formation. Conversely, excessive stress (4 and 6 g/cm²) or extreme prolonged loading (24 h) suppressed vitality and down-regulated angiogenic markers.

Compressive stress dynamically modulates DPC angiogenesis in a magnitude-dependent manner, primarily governed by the PIEZO1-YAP/TAZ mechanotransduction axis. Optimal mild compression (2 g/cm²) effectively enhanced the intrinsic angiogenic response, providing a novel mechanobiological strategy for pulp regeneration.