title: Treponema denticola upregulates MMP-2 activation in periodontal ligament cells: interplay between epigenetics and periodontal infection.
abstract: OBJECTIVE
  Periodontal pathogens initiate chronic dysregulation of inflammation and tissue homeostasis that characterize periodontal disease. To better understand oral microbe-host tissue interactions, we investigated expression and activation of MMP-2 in periodontal ligament cells following Treponema denticola challenge.
  
  
  METHODS
  Cultured PDL cells were challenged with T. denticola, and bacterial adherence, internalization and survival were assayed by immunofluorescence microscopy and antibiotic protection assays, respectively. MMP-2 activation was detected by zymography. MMP-2, MT1/MMP and TIMP-2 expression following T. denticola challenge was determined by qRT-PCR. Promoter methylation of MMP-2 and MT1/MMP was screened by methylation-sensitive restriction analysis and by bisulfite DNA sequencing.
  
  
  RESULTS
  T. denticola adhered to and was internalized by PDL cells but did not survive intracellularly beyond 24h. Importantly, while dentilisin activity in PDL culture supernatants gradually decreased following T. denticola challenge, MMP-2 activation persisted for up to 5 days, suggesting involvement of other regulatory mechanisms. Transcription and expression of MT1/MMP and TIMP-2 increased in response to T. denticola challenge. However, consistent with previously reported constitutive pro-MMP-2 expression in PDL cells, the MMP-2 promoter was hypomethylated, independent of T. denticola challenge.
  
  
  CONCLUSIONS
  MMP-2 promoter hypomethylation is consistent with constitutive pro-MMP-2 expression in PDL cells. This, coupled with T. denticola-mediated upregulation of MMP-2-related genes and chronic activation of pro-MMP-2, mimics key in vivo mechanisms of periodontal disease chronicity, in particular MMP-2-dependent matrix degradation and bone resorption. Adherence and/or internalization of T. denticola may contribute to these processes by one or more regulatory mechanisms, including contact-dependent signal transduction or other epigenetic mechanisms.
authors: Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, United States.
authors: Di
authors: D
authors: Miao
authors: Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, United States.
authors: Valentina
authors: V
authors: Godovikova
authors: Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, United States.
authors: Xu
authors: X
authors: Qian
authors: Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, United States.
authors: Suchithra
authors: S
authors: Seshadrinathan
authors: Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, United States.
authors: Yvonne L
authors: YL
authors: Kapila
authors: Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, United States. Electronic address: fenno@umich.edu.
authors: J Christopher
authors: JC
authors: Fenno
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D010513:Periodontal Ligament / Q000166:cytology* / Q000201:enzymology*; D010518:Periodontitis / Q000378:metabolism / Q000382:microbiology; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D015533:Transcriptional Activation; D048373:Treponema denticola / Q000502:physiology*; D015854:Up-Regulation
chemical_list: C560823:TIMP2 protein, human; D019716:Tissue Inhibitor of Metalloproteinase-2; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2
keywords: Epigenetics; MMP-2; MT1/MMP; Proteases; TIMP-2; Treponema