Proinflammatory effects of factor Xa on human dental pulp cells

Dental pulp plays a crucial role in tooth homeostasis, and inflammation often leads to irreversible damage. Factor Xa (FXa), known for its role in coagulation, has recently been identified as an inflammatory mediator that acts via protease-activated receptor (PAR)-2 signaling. We herein investigated the PAR-2-mediated inflammatory response induced by FXa in human dental pulp cells (HDPC) by assessing COX-2 expression and prostaglandin E₂ (PGE₂) levels.

HDPCs were isolated from outgrowth cultures from extracted third molars and cultured in α-minimum essential medium containing 10 % fetal bovine serum. FXa was applied in a time- and concentration-dependent manner and COX-2 expression and PGE₂ production were evaluated using real-time RT-PCR, western blotting, and enzyme immunoassays. PAR-2 localization in inflamed pulp tissue was assessed using immunohistochemistry. Intracellular kinase phosphorylation was analyzed using a phosphokinase array. Inhibitor experiments with AZ3451, rivaroxaban, and static were conducted to examine PAR-2, FXa, and signal transducers and activators of transcription (STAT)3 involvement in the signaling pathway.

FXa promoted COX-2 expression and PGE₂ production in HDPCs in a time- and concentration-dependent manner. Immunohistochemical analysis revealed localization of PAR-2-positive cells in inflamed human pulp tissues. Phosphokinase array analysis revealed enhanced STAT3 phosphorylation, and inhibition of PAR-2, FXa, and STAT3 suppressed COX-2 expression.

This study demonstrated that FXa induces COX-2 expression and PGE₂ production in HDPCs via PAR-2 and STAT3 signaling. These findings enhance our understanding of pulp inflammation and may support the development of new therapeutic approaches for dental pulp preservation.