title: Lipopolysaccharide differentially affects the osteogenic differentiation of periodontal ligament stem cells and bone marrow mesenchymal stem cells through Toll-like receptor 4 mediated nuclear factor κB pathway.
abstract: BACKGROUND
  Periodontitis is initiated and sustained by bacteria. However, the mechanism of bacteria induced periodontitis is still unknown. We hypothesized that bacterial components can affect the functions of stem cells in the periodontium. In this study, we comparatively investigated the influence of Lipopolysaccharide (LPS) on the osteogenesis potential of human periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMMSCs).
  
  
  METHODS
  Human PDLSCs and BMMSCs were harvested and mineralized nodule formation was assessed by alizarin red S staining. Expression level of osteogenic related gene was detected by quantitative RT-PCR (qRT-PCR). The expression of Toll-like receptor 4 (TLR4) and its downstream signaling pathway were examined by western blot. The role of TLR4 and related signaling pathway in LPS impairing the osteogenic potential of human PDLSCs and BMMSCs were also studied by alizarin red S staining and qRT-PCR. Experimental periodontitis was induced in adult Sprague-Dawley rats and the alveolar bone loss was measured by micro computed tomography analysis. The expression of alkaline phosphatase (ALP) was assessed by immunohistochemistry and the number of osteoclasts was shown by Tartrate-resistant acid phosphatase (TRAP) staining.
  
  
  RESULTS
  LPS decreased the osteogenic differentiation of human PDLSCs through TLR4 regulated nuclear factor (NF)-κB pathway, but not for BMMSCs. Blocking TLR4 or NF-κB signaling partially reversed the decreased osteogenic potential of PDLSCs and prevented the alveolar bone loss caused by LPS experimental periodontitis in rats. The ALP expression in the periodontal ligament was elevated after treatment with anti-TLR4 antibody or pyrrolidinedithiocarbamate, whereas there was no statistical significance among groups for the number of osteoclasts.
  
  
  CONCLUSIONS
  These data suggest that LPS can activate TLR4 regulated NF-κB pathway of human PDLSCs, thus decreasing their osteogenic potential. Blockage of TLR4 or NF-κB pathway might provide a new approach for periodontitis treatment.
authors.forename: Chenghua
authors.initials: C
authors.lastname: Li
authors.forename: Bei
authors.initials: B
authors.lastname: Li
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Dong
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: Xiaoning
authors.initials: X
authors.lastname: He
authors.forename: Li
authors.initials: L
authors.lastname: Liao
authors.forename: Chenghu
authors.initials: C
authors.lastname: Hu
authors.forename: Qintao
authors.initials: Q
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006801:Humans; D008070:Lipopolysaccharides / Q000633:toxicity*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology; D010012:Osteogenesis / Q000502:physiology; D010513:Periodontal Ligament / Q000166:cytology; D010518:Periodontitis / Q000378:metabolism* / Q000382:microbiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4