Prostaglandin Transporting Protein-mediated Prostaglandin E₂ Transport in Lipopolysaccharide-inflamed Rat Dental Pulp

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• 作者：Naoto Ohkura ; DDS ; Yoshimi Shigetani ; DDS ; PhD ; Nagako Yoshiba ; DDS ; PhD ; Kunihiko Yoshiba ; DDS ; PhD ; Takashi Okiji ; DDS ; PhD ; ^{t-okiji@dent.niigata-u.ac.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Dental pulp ; endothelial cell ; multidrug resistance-associated protein 4 ; prostaglandin E2 ; prostaglandin transporter ; pulp inflammation ; rat
• 刊名：Journal of Endodontics
• 出版年：2014
• 出版时间：August 2014
• 年：2014
• 卷：40
• 期：8
• 页码：1112-1117
• 全文大小：2020 K

文摘

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).

Conclusion

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.