PAR-1 and PAR-2 Expression Is Enhanced in Inflamed Odontoblast Cells

Abstract

Protease-activated receptors (PARs) are G protein-coupled receptors, which are activated by proteolytical cleavage of the amino-terminus and act as sensors for extracellular proteases. We hypothesized that PAR-1 and PAR-2 can be modulated by inflammatory stimulus in human dental pulp cells. PAR-1 and PAR-2 gene expression in human pulp tissue and MDPC-23 cells were analyzed by quantitative polymerase chain reaction. Monoclonal PAR-1 and PAR-2 antibodies were used to investigate the cellular expression of these receptors using Western blot, flow cytometry, and confocal microscopy in MDPC-23 cells. Immunofluorescence assays of human intact and carious teeth were performed to assess the presence of PAR-1 and PAR-2 in the dentin-pulp complex. The results show for the first time that human odontoblasts and MDPC-23 cells constitutively express PAR-1 and PAR-2. PAR-2 activation increased significantly the messenger RNA expression of matrix metalloproteinase (MMP)-2, MMP-9, MMP-13, and MMP-14 in MDPC-23 cells ( P < 0.05), while the expression of these enzymes decreased significantly in the PAR-1 agonist group ( P < 0.05). The high-performance liquid chromatography and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis showed the presence of MMP-13 activity cleaving PAR-1 at specific, noncanonical site TLDPRS↓FLL in human dental pulp tissues. Also, we detected a presence of a trypsin-like activity cleaving PAR-2 at canonical site SKGR↓SLIGRL in pulp tissues. Confocal microscopy analysis of human dentin-pulp complex showed intense positive staining of PAR-1 and PAR-2 in the odontoblast processes in dentinal tubules of carious teeth compared to intact ones. The present results support the hypothesis of activation of the upregulated PAR-1 and PAR-2 by endogenous proteases abundant during the inflammatory response in dentin-pulp complex.

The healthy root pulp, degradation and regeneration

“…Immunostaining of the dental-pulp complex region showed that labeling was 1.9-fold more intensive for PAR-2 compared to PAR-1. The results presented by Alvarez et al, 63 support the hypothesis of activation of upregulated PAR-1 and PAR-2 by endogenous proteases abundant during the inflammatory response in dentin-pulp complex.…”

“…Four members of the PAR family (PAR-1 to PAR-4) have been described. 63 Odontoblasts orchestrate the pulpal inflammatory response by producing a variety of cytokines and chemokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-8, TLR2, and TLR4. The stimulation of PAR promoted a significant increase in the gene expression of MMP-2, MMP-9, MMP-13, and MMP-14.…”

Recruited CD68+CD206+ macrophages orchestrate graft immune tolerance to prompt xenogeneic-dentin matrix-based tooth root regeneration

“…TDM undergo demineralization and subsequently release the major molecules to mediate neighboring odontogenesis, such as col-I, DMP1, and DSPP [15] . The proteins-induced cellular response colluded with matrix metalloproteinases (MMPs), which in return degraded these proteins [ 31 , 32 ] and resulted in aberrant absorptions of xeno-complex in primates’ model. Yet, serious adverse reactions are little reported even though fibrosis outcomes of xenogeneic ECM products in humans.…”

Effects of acids, pepsin, bile acids, and trypsin on laryngopharyngeal reflux diseases: physiopathology and therapeutic targets

“…PAR-2 is involved in intestinal inflammation and the neurogenic inflammatory epithelial response. It is expressed in esophageal epithelial cells [54], odontoblasts [55], sinus epithelial ciliated cells [56] and others.…”