title: Prostaglandin transporting protein-mediated prostaglandin E2 transport in lipopolysaccharide-inflamed rat dental pulp.
abstract: BACKGROUND
  The prostaglandin transporter (Pgt) and multidrug resistance-associated protein (Mrp) 4 are membrane transport proteins that play crucial roles in the transmembrane uptake and/or efflux of prostaglandins (PGs). This study attempted to analyze the protein expression of Pgt and Mrp4 and their involvement in PGE2 efflux transport in lipopolysaccharide (LPS)-inflamed rat incisor pulp tissue.
  
  
  METHODS
  Pulpitis was induced in the upper incisors of Wistar rats by treating them with LPS for 24 hours. The protein expression levels of Pgt, Mrp4, and microsomal PGE synthase (mPGES) were analyzed with immunofluorescent staining. The amount of PGE2 released from the inflamed pulp tissue in the presence or absence of dipyridamole (an Mrp4 inhibitor) was assessed by using an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Double immunofluorescence staining revealed that the Pgt, Mrp4, and mPGES immunoreactivity co-localized in CD31-expressing endothelial cells. Moreover, the Mrp4 inhibitor caused a significant decrease in the amount of PGE2 released from the LPS-inflamed pulp (P < .01 at 24 hours).
  
  
  CONCLUSIONS
  Pgt, Mrp4, and mPGES expression was detected in the endothelial cells of normal and LPS-inflamed rat incisor pulp tissue, suggesting that these cells are associated with the biosynthesis and transmembrane transport of PGE2. The significant decrease in PGE2 release induced by the Mrp4 inhibitor suggests that Mrp4 contributes to the transport of PGE2 in the transmembrane efflux pathway.
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Naoto
authors: N
authors: Ohkura
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Yoshimi
authors: Y
authors: Shigetani
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Nagako
authors: N
authors: Yoshiba
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Kunihiko
authors: K
authors: Yoshiba
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. Electronic address: t-okiji@dent.niigata-u.ac.jp.
authors: Takashi
authors: T
authors: Okiji
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D003782:Dental Pulp / Q000378:metabolism / Q000473:pathology; D015232:Dinoprostone / Q000032:analysis / Q000378:metabolism*; D004176:Dipyridamole / Q000494:pharmacology; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology; D004926:Escherichia coli; D019746:Intramolecular Oxidoreductases / Q000032:analysis; D008070:Lipopolysaccharides / Q000009:adverse effects*; D008264:Macrophages / Q000473:pathology; D008297:Male; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009504:Neutrophils / Q000473:pathology; D027361:Organic Anion Transporters / Q000032:analysis / Q000378:metabolism*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D000071876:Prostaglandin-E Synthases; D011671:Pulpitis / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013047:Specific Pathogen-Free Organisms; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D015232:Dinoprostone; D004176:Dipyridamole; D019746:Intramolecular Oxidoreductases; D008070:Lipopolysaccharides; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D027361:Organic Anion Transporters; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D000071876:Prostaglandin-E Synthases; C073492:ABCC4 protein, human; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C503526:SLCO2A1 protein, human
keywords: Dental pulp; endothelial cell; multidrug resistance-associated protein 4; prostaglandin E2; prostaglandin transporter; pulp inflammation; rat