Distinctive genetic activity pattern of the human dental pulp between deciduous and permanent teeth.

Ji-Hee Kim,Jae-Ho Lee,Je-Seon Song,Mijeong Jeon,Byung-Jai Choi,Seok Jun Moon,Seong-Oh Kim,Pamela K Denbesten,Han-Sung Jung,Irina Kerkis

doi:10.1371/journal.pone.0102893

Abstract

Human deciduous and permanent teeth exhibit different developmental processes, morphologies, histological characteristics and life cycles. In addition, their pulp tissues react differently to external stimuli, such as the pulp sensitivity test, dental trauma and pulp therapy materials. These suggest differences in gene expression and regulation, and in this study we compared gene-expression profiles of the human dental pulp from deciduous and permanent teeth. Pulp tissues from permanent premolars and deciduous molars aged 11–14 years were extirpated and mRNA was isolated for cDNA microarray analysis, and quantitative real-time PCR (qPCR). Other teeth were used for immunohistochemical analysis (IHC). Microarray analysis identified 263 genes with a twofold or greater difference in expression level between the two types of pulp tissue, 43 and 220 of which were more abundant in deciduous and permanent pulp tissues, respectively. qPCR analysis was conducted for eight randomly selected genes, and the findings were consistent with the cDNA microarray results. IHC confirmed that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) was broadly expressed in deciduous dental pulp tissue, but minimally expressed in permanent dental pulp tissue. Immunohistochemical analysis showed that calbindin 1 (CALB1), leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), and gamma-aminobutyric acid A receptor beta 1 (GABRB1) were abundantly expressed in permanent predentin/odontoblasts, but only minimally expressed in deciduous dental pulp tissue. These results show that deciduous and permanent pulp tissues have different characteristics and gene expression, suggesting that they may have different functions and responses to therapies focused on pulp or dentin regeneration.

Highlights

Human have two dentitions, deciduous and permanent
Among deciduous teeth presenting with pulp canal obliteration, 90% resorb normally, and treatment in the primary dentition is usually not indicated [5], whereas pulp obliterations in permanent teeth can alter the outcome of endodontic treatments [6]
Gene ontology analysis To translate the data into a more meaningful biological context and to characterize more thoroughly the sets of functionally related genes, the differentially expressed data sets were organized into Gene Ontology Consortium (GO) grouping using the DAVID Web-based tool

Summary

Introduction

Deciduous and permanent. Deciduous teeth develop first making small buds from the oral epithelium into mesenchyme. The deciduous and permanent teeth exhibit distinctive developmental processes, morphologies, histological characteristics and life cycles. Their pulp tissues react differently to external stimuli, such as the pulp sensitivity test, dental trauma and pulp therapy materials. Application of calcium hydroxide to permanent teeth as part of the medication for direct pulp capping induces the deposition of hard tissue as reparative dentin in permanent but not deciduous pulp [7]. These morphologic, histologic, and functional differences of the pulp tissue in permanent and deciduous teeth may signify differences in their gene-expression patterns

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Conclusion