Compressive Force Upregulates Notch Target Genes and NOTCH2 mRNA in Human Dental Pulp Cells

Dental pulp cells encounter compressive force in various situations. While mechanical force can produce various effects on dental pulp cells, the mechanisms underlying their response remain unclear. In this study, we examined the mRNA expression of Notch target genes and Notch receptors in human dental pulp cells (HDPCs) under mechanical compressive force. We utilized two in vitro compressive force application models, direct compression and hydrostatic compression. The results showed that there was an upregulation of Notch target gene, HES1, in HDPCs subjected to the compressive force generated by both models for 2 hours. Hydrostatic compression also upregulated HES1 and HEY1 mRNA expression following 6 hours of force application. NOTCH2 was the only Notch receptor found to be upregulated in HDPCs following compressive force application, in which the upregulation was observed at 6 hours after hydrostatic compression. In conclusion, both hydrostatic and direct compressive forces can upregulate the mRNA expression of Notch target gene, HES1, in HDPCs. However, the hydrostatic compression model produced more prolonged activation of HES1 and it also stimulated the upregulation of HEY1 as well as NOTCH2.