Acid Dentin Lysates Increase Amelotin Expression in Oral Epithelial Cells and Gingival Fibroblasts

Jila Nasirzade,Reinhard Gruber,Layla Panahipour,Zahra Kargarpour

doi:10.3390/app11125394

Jila Nasirzade, Reinhard Gruber + Show 2 more

Open Access

https://doi.org/10.3390/app11125394

Copy DOI

Abstract

Amelotin (AMTN) is a secretory calcium-binding phosphoprotein controlling the adhesion of epithelial cells to the tooth surface, forming a protective seal against the oral cavity. It can be proposed that signals released upon dentinolysis increase AMTN expression in periodontal cells, thereby helping to preserve the protective seal. Support for this assumption comes from our RNA sequencing approach showing that gingival fibroblasts exposed to acid dentin lysates (ADL) greatly increased AMTN expression. In the present study, we confirm that acid dentin lysates significantly increase AMTN in gingival fibroblasts and extend this observation towards the epithelial cell lineage by use of the HSC2 oral squamous and TR146 buccal carcinoma cell lines. AMTN immunostaining revealed an intensive signal in the nucleus of HSC2 cells exposed to acid dentin lysates. Acid dentin lysates mediate their effect via the transforming growth factor (TGF)-β type 1 receptor kinase as the antagonist SB431542 abolished the expression of AMTN in the epithelial cells and fibroblasts. Similar to what is known for fibroblasts, acid dentin lysate increased Smad-3 phosphorylation in HSC2 cells. HSC2 cells also respond to the AMTN-stimulating activity of the dentin lysate when adsorbed to gelatin. When simulating regenerative approaches, enamel matrix derivative, TGF-β1, and bone morphogenetic protein-2 also caused a robust increase in SB431542-dependent AMTN expression in HSC2. Taken together, we show here that acid dentin lysate uses the TGF-β-depended signaling pathway to support the AMTN expression in epithelial cells, possibly helping in maintaining the protective seal against the oral cavity.

Highlights

The periodontium is the tooth-supporting tissue that anchors the tooth roots within the alveolar bone, and seals erupted teeth towards the oral cavity [1,2]
To evaluate the effects of acid dentin lysates (ADL) on the expression of AMTN and three main matrix enamel proteins, namely amelogenin (AMG), ameloblastin (AMBN), and enamelin (ENAM), RT-PCR analysis of the respective genes was conducted in human oral squamous cell line (HSC2), buccal carcinoma cell line (TR146), and gingival fibroblast (GF)
The expression of odontogenic ameloblast-associated protein (ODAM) [6] as an interacting protein with AMTN was not regulated by ADL

Summary

Introduction

The periodontium is the tooth-supporting tissue that anchors the tooth roots within the alveolar bone, and seals erupted teeth towards the oral cavity [1,2]. Attachment of the junctional epithelial cells to the enamel tooth crown made and the cementum layer covering the root dentin is of imperative importance for maintaining the integrity of the periodontium [3,4]. This seal arises from the later stages of tooth development when parts of the epithelial enamel organ fuse with the oral epithelium forming the junctional epithelium [5]. The molecular signals causing the periodontal cells to produce the specialized basal lamina are beginning to be discovered

Objectives

Methods

Results

Conclusion