PAR-1 and PAR-2 Expression Is Enhanced in Inflamed Odontoblast Cells. (December 2017)

• Record Type: Journal Article
• Authors: Alvarez, M.M.P.; Moura, G.E.; Machado, M.F.M.; Viana, G.M.; de Souza Costa, C.A.; Tjäderhane, L.; Nader, H.B.; Tersariol, I.L.S.; Nascimento, F.D.
• Is Part Of: Journal of dental research. Volume 96:Number 13(2017)
• Page Start: 1518
• Page End: 1525
• Publication Date: 2017-12
• Subjects: proteinase-activated receptor (PAR) -- dentin-pulp complex -- odontoblasts -- caries -- proteolytic enzymes -- matrix metalloproteinases; Dentistry -- Periodicals; Dentistry -- Social aspects -- Periodicals; Dentistry -- Periodicals; Research -- Periodicals; 617.6005
• DOI: 10.1177/0022034517719415
• Languages: English
• ISSNs: 0022-0345

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 42 ↓ F 43 LL in human dental pulp tissues. Also, we detected a presence of a trypsin-like activity cleaving PAR-2 at canonical site SKGR 20 ↓ S 21 LIGRL 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.