Emdogain-regulated gene expression in palatal fibroblasts requires TGF-βRI kinase signaling.

Alexandra Stähli,Reinhard Gruber,Anton Sculean,Dieter Bosshardt

doi:10.1371/journal.pone.0105672

Abstract

Genome-wide microarrays have suggested that Emdogain regulates TGF-β target genes in gingival and palatal fibroblasts. However, definitive support for this contention and the extent to which TGF-β signaling contributes to the effects of Emdogain has remained elusive. We therefore studied the role of the TGF-β receptor I (TGF-βRI) kinase to mediate the effect of Emdogain on palatal fibroblasts. Palatal fibroblasts were exposed to Emdogain with and without the inhibitor for TGF-βRI kinase, SB431542. Emdogain caused 39 coding genes to be differentially expressed in palatal fibroblasts by microarray analysis (p<0.05; >10-fold). Importantly, in the presence of the TGF-βRI kinase inhibitor SB431542, Emdogain failed to cause any significant changes in gene expression. Consistent with this mechanism, three independent TGF-βRI kinase inhibitors and a TGF-β neutralizing antibody abrogated the increased expression of IL-11, a selected Emdogain target gene. The MAPK inhibitors SB203580 and U0126 lowered the impact of Emdogain on IL-11 expression. The data support that TGF-βRI kinase activity is necessary to mediate the effects of Emdogain on gene expression in vitro.

Highlights

Emdogain consists of enamel matrix derivatives and the vehicle propylene glycol alginate (Institut Straumann, Basel, Switzerland) [1]
To rule out any toxic effect of the TGF-b receptor I (TGF-bRI) kinase inhibitor, palatal fibroblasts were incubated with Emdogain with and without SB431542 before life-dead staining (Figure 2A) and MTT assay (Figure 2B) were performed
To study the role of the TGF-bRI kinase to mediate the effect of Emdogain in vitro, isolated palatal fibroblasts from three donors were exposed to Emdogain with and without the inhibitor SB431542 and a genome-wide microarray was performed

Summary

Introduction

Emdogain consists of enamel matrix derivatives and the vehicle propylene glycol alginate (Institut Straumann, Basel, Switzerland) [1]. The local application of Emdogain has been shown to support skin wound healing [2,3]. The cellular and molecular mechanisms allowing Emdogain to support tissue regeneration have not been clarified so far. In vitro studies support the assumption that Emdogain directly targets cells that are involved in wound healing. Emdogain modulates the formation of extracellular matrix and modulates the differentiation of mesenchymal cells [10,11]. Emdogain can be taken up by periodontal ligament fibroblasts [12] and can change the mitogenic activity of cells [13]. Among the genes that are expressed in response to Emdogain are cytokines [14]. The in vitro cellular responses to Emdogain have been summarized recently [1,15]

Methods

Results

Conclusion