Transient receptor potential melastatin (TRPM) 8 is expressed in freshly isolated native human odontoblasts. (March 2017)

• Record Type: Journal Article
• Authors: Tazawa, Kento; Ikeda, Hideharu; Kawashima, Nobuyuki; Okiji, Takashi
• Is Part Of: Archives of oral biology. Volume 75(2017)
• Page Start: 55
• Page End: 61
• Publication Date: 2017-03
• Subjects: DAPI 4′, 6-diamidino-2-phenylindole -- DMP1 dentin matrix protein 1 -- DSPP dentin sialophosphoprotein -- GAPDH glyceraldehyde 3-phosphate dehydrogenase -- TRP transient receptor potential -- TRPA1 transient receptor potential ankyrin 1 -- TRPM8 transient receptor potential melastatin 8 -- PCR polymerase chain reaction -- qRT-PCR quantitative reverse transcription polymerase chain reaction -- RT-PCR reverse transcription polymerase chain reaction; TRP channels -- Odontoblast -- Dental pulp -- Human -- Thermosensing; Mouth -- Periodicals; Mouth -- Diseases -- Periodicals; Dentistry -- Periodicals; Electronic journals; 617.6005
• DOI: 10.1016/j.archoralbio.2016.12.007
• Languages: English
• ISSNs: 0003-9969

Abstract

Highlights: Expression of TRPM8 immunoreactivity was confirmed in the odontoblastic layer. Isolated odontoblasts expressed TRPM8 immunoreactivity. They expressed a higher TRPM8 mRNA level than inner pulp tissues. Expression of TRPA1 was not detected in isolated odontoblasts collected from healthy human teeth. Abstract: Objective: Cold-sensitive ion channels, such as transient receptor potential melastatin (TRPM) 8 and transient receptor potential ankyrin (TRPA) 1, may play a crucial role in the nociceptive function of odontoblasts, whereas expression of these TRP channels in human native odontoblasts remains to be elucidated. This study aimed to analyze the expression of TRPM8 and TRPA1 in freshly isolated native human odontoblasts. Design: Odontoblasts were isolated from freshly extracted healthy human teeth (n = 4); after removing the inner pulp tissues from the pulp chambers, odontoblasts remaining on the dentin surface were washed out with phosphate buffered saline and collected. Reverse transcription-polymerase chain reaction was employed to compare the expression levels of TRPM8, TRPA1, and dentin matrix acidic phosphoprotein 1 ( DMP1) mRNAs between the isolated odontoblasts and the inner pulp tissues. The isolated cells were subjected to immunolocalization of TRPM8 and nestin. Paraformaldehyde-fixed, EDTA-demineralized frozen sections obtained from freshly extracted healthy human teeth (n = 4) were also analyzed immunohistochemically using anti-nestin, TRPM8, and TRPA1 antibodies. Results: Expression levels of TRPM8 and DMP1 in the isolated odontoblasts were significantly higher than those in the inner pulp tissues ( p < 0.05). Expression of TRPM8 and nestin was observed in the odontoblastic layer of the dental pulp tissue and isolated odontoblasts, while expression of TRPA1 was not detected. Conclusions: TRPM8, but not TRPA1, was detected in freshly isolated native human odontoblasts at the protein and mRNA levels, suggesting that odontoblasts play an important role in detecting external cold stimulation via TRPM8 in healthy condition.