Piezo1 participates in the tension-driven osteogenic differentiation of periodontal ligament stem cells

Orthodontic tooth movement involves osteogenesis of periodontal ligament stem cells (PDLSCs) in response to tension force. Piezo1 was recognized as a mechanically sensitive channel in 2010, capable of activation by tension force. However, its specific role in tension-induced osteogenic differentiation of PDLSCs remains unclear. This study aims to investigate the involvement Piezo1 in this process. Human PDLSCs were cultured and characterized. Following exposure to half-sine periodic tensile stress (0.1 Hz, 12% elongation) for durations of 0, 1, 3, 6, 9, and 12 h using a Flexcell tension system, phalloidin staining and CCK-8 assays were used to assess the actin cytoskeleton and cell viability, respectively, of PDLSCs. The expression levels of Piezo1 and Ca2+/calmodulin -dependent protein kinase (CaMKII), as well as CaMKII phosphorylation and calcium influx were evaluated in PDLSCs. The osteogenic factors expression levels (Runt-related transcription factor 2 [Runx2] and alkaline phosphatase [ALP]), together with ALP staining and measurement of ALP activity, were evaluated to characterize osteogenic potential of PDLSCs. Besides, the levels of Yes-associated protein (YAP), and β-catenin as mechanosensitive signaling molecules were also assessed. After application of the tension force, the PDLSCs exhibited a more extensive spreading morphology, while there were no significant differences in cell viability among the 0, 1, 3, 6, 9, and 12 h groups. PDLSCs exhibited increased osteogenic potential, shown by upregulation of Runx2 and ALP and increased ALP activity after tension force application. Increased expression of Piezo1, accompanied by elevated calcium influx and enhanced CaMKII expression and phosphorylation, was observed in the stretched PDLSCs. The levels of the mechanosensitive signaling molecules YAP and β-catenin also increased in response to the tension force. Tension force promotes Piezo1 expression and osteogenic differentiation in PDLSCs. It also enhances calcium influx, CaMKII expression and phosphorylation, and the expression of YAP and β-catenin. Piezo1 participate in the osteogenic differentiation of hPDLSCs under tension force, providing new insights into the molecular mechanisms of osteogenic differentiation in PDLSCs and suggest potential therapeutic targets for modulating bone remodeling during orthodontic tooth movement.