Interactions of anaerobic bacteria with dental stem cells: an in vitro study.

Anne Biedermann,Hermann Lang,Bernd Kreikemeyer,Katja Kriebel,Salomon Amar

doi:10.1371/journal.pone.0110616

Abstract

BackgroundIn patients with periodontitis, it is highly likely that local (progenitor) cells encounter pathogenic bacteria. The purpose of this in vitro study was to elucidate how human dental follicle stem cells (hDFSC) react towards a direct challenge with anaerobic periodontal pathogens under their natural oxygen-free atmosphere. HDFSC were compared to human bone marrow mesenchymal stem cells (hBMSC) and differentiated primary human gingival fibroblasts (hGiF), as well as permanent gingival carcinoma cells (Ca9-22).Methodology/Principal FindingsThe different cell types were investigated in a co-culture system with Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum). The viability of the cells and pathogens under anaerobic conditions, as well as interactions in terms of adherence and internalization, were examined. Additionally, the release of pro-inflammatory interleukin-8 (IL-8) and anti-inflammatory interleukin-10 (IL-10) was quantified via enzyme-linked immunosorbent assay. The bacteria adhered less efficiently to hDFSC compared to Ca9-22 (P. gingivalis: 0.18% adherence to hDFSC; 3.1% adherence to Ca9-22). Similar results were observed for host cell internalization (F. nucleatum: 0.002% internalization into hDFSC; 0.09% internalization into Ca9-22). Statistically significantly less IL-8 was secreted from hDFSC after stimulation with F. nucleatum and P. gingivalis in comparison with hGiF (F. nucleatum: 2080.0 pg/ml – hGiF; 19.7 pg/ml – hDFSC). The IL-10 response of the differentiated cells was found to be low in relation to their pro-inflammatory IL-8 response.Conclusions/SignificanceThe results indicate that dental stem cells are less prone to interactions with pathogenic bacteria than differentiated cells in an anaerobic environment. Moreover, during bacterial challenge, the stem cell immune response seems to be more towards an anti-inflammatory reaction. For a potential future therapeutic use of hDFSC, these findings support the idea of a save application.

Highlights

To determine the biological role of dental stem cells in their natural environment and to examine the save potential therapeutic application for tissue regeneration, the understanding of cell– bacteria interactions is of great importance [1].The periodontal tissues are composed of a variety of different cell types
We concluded that coculture with anaerobic bacteria and human dental follicle stem cells (hDFSC) was possible
We demonstrate that hDFSC show less interaction with periodontal pathogens concerning adherence and internalization

Summary

Introduction

To determine the biological role of dental stem cells in their natural environment and to examine the save potential therapeutic application for tissue regeneration, the understanding of cell– bacteria interactions is of great importance [1].The periodontal tissues are composed of a variety of different cell types. The dental follicle harbors human dental follicle stem cells (hDFSC), and is present in impacted teeth, which are commonly extracted and disposed of medical waste in dental practice [5]. These cells are an accessible cell source for experimental and future clinical applications in periodontal tissue or bone regeneration approaches [6,5]. It is highly likely that local (progenitor) cells encounter pathogenic bacteria The purpose of this in vitro study was to elucidate how human dental follicle stem cells (hDFSC) react towards a direct challenge with anaerobic periodontal pathogens under their natural oxygen-free atmosphere. HDFSC were compared to human bone marrow mesenchymal stem cells (hBMSC) and differentiated primary human gingival fibroblasts (hGiF), as well as permanent gingival carcinoma cells (Ca9-22)

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