title: Porphyromonas gingivalis promotes the cell cycle and inflammatory cytokine production in periodontal ligament fibroblasts.
abstract: OBJECTIVE
  The infection of Porphyromonas gingivalis (P. gingivalis) modulates host immune-inflammatory responses and destructs homeostasis of normal cell cycle, thereby leading to periodontal tissue destruction. Human periodontal ligament fibroblasts (PDLFs) are key players in the host immune responses and periodontal tissue regeneration. The aim of the present study was to discover the effects of P. gingivalis infection on the cell cycle and inflammatory cytokine production in PDLFs.
  
  
  METHODS
  P. gingivalis infection model into PDLFs was established. The effect of P. gingivalis on the cell proliferation and cell cycle were detected by MTT and flow cytometry. The p21, cyclin D1 and cyclin E mRNA expression, p21 protein expression, as well as IL-6 and IL-8 protein levels were analyzed by RT-qPCR, Western blot and ELISA, respectively.
  
  
  RESULTS
  P. gingivalis promoted proliferation and G1 phase of PDLFs. G1 phase promotion was associated with the decreased level of p21 and the up-regulation of cyclin D1 at 6h, and with the increased level of cyclin E at 12h. Simultaneously, the immune-inflammatory response of PDLFs was initiated by P. gingivalis during the initial stage of infection, including the increased expressions of IL-6 and IL-8.
  
  
  CONCLUSIONS
  We confirmed that the infection of P. gingivalis could modulate the expression of PDLF genes, which control cell cycle and inflammatory cytokine production. Thus, P. gingivalis may contribute to the proliferation and inflammation of periodontal tissue.
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: cc3092956294@126.com.
authors.forename: Junchao
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: lin_hope@sina.com.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Tang
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: lichen1980716@163.com.
authors.forename: Chen
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: chunlingpan@163.com.
authors.forename: Chunling
authors.initials: C
authors.lastname: Pan
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: phebahoney@163.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: gfx1989_@126.com.
authors.forename: Fengxue
authors.initials: F
authors.lastname: Geng
authors.affiliation: Department of Periodontics and Oral Biology, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, Liaoning Province, China. Electronic address: yppan@mail.cmu.edu.cn.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Pan
mesh_terms: D015153:Blotting, Western; D002453:Cell Cycle; D049109:Cell Proliferation; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000378:metabolism*; D019927:Cyclin E / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D010513:Periodontal Ligament / Q000166:cytology*; D016966:Porphyromonas gingivalis / Q000276:immunology*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D019927:Cyclin E; D050759:Cyclin-Dependent Kinase Inhibitor p21; D012333:RNA, Messenger; D019938:Cyclin D1
keywords: Cell cycle; Cytokines; Periodontal ligament fibroblasts; Periodontitis; Porphyromonas gingivalis