title: Establishment and characterization of a telomerase immortalized human gingival epithelial cell line.
abstract: OBJECTIVE
  Gingival keratinocytes are used in model systems to investigate the interaction between periodontal bacteria and the epithelium in the initial stages of the periodontal disease process. Primary gingival epithelial cells (GECs) have a finite lifespan in culture before they enter senescence and cease to replicate, while epithelial cells immortalized with viral proteins can exhibit chromosomal rearrangements. The aim of this study was to generate a telomerase immortalized human gingival epithelial cell line and compare its in vitro behaviour to that of human GECs.
  
  
  METHODS
  Human primary GECs were immortalized with a bmi1/hTERT combination to prevent cell cycle triggers of senescence and telomere shortening. The resultant cell-line, telomerase immortalized gingival keratinocytes (TIGKs), were compared to GECs for cell morphology, karyotype, growth and cytokeratin expression, and further characterized for replicative lifespan, expression of toll-like receptors and invasion by P. gingivalis.
  
  
  RESULTS
  TIGKs showed morphologies, karyotype, proliferation rates and expression of characteristic cytokeratin proteins comparable to GECs. TIGKs underwent 36 passages without signs of senescence and expressed transcripts for toll-like receptors 1-6, 8 and 9. A subpopulation of cells underwent stratification after extended time in culture. The cytokeratin profiles of TIGK monolayers were consistent with basal cells. When allowed to stratify, cytokeratin profiles of TIGKs were consistent with suprabasal cells of the junctional epithelium. Further, TIGKs were comparable to GECs in previously reported levels and kinetics of invasion by wild-type P. gingivalis and an invasion defective ΔserB mutant.
  
  
  CONCLUSIONS
  Results confirm bmi1/hTERT immortalization of primary GECs generated a robust cell line with similar characteristics to the parental cell type. TIGKs represent a valuable model system for the study of oral bacteria interactions with host gingival cells.
authors: Center for Oral Health and Systemic Disease, School of Dentistry, University of Louisville, Louisville, KY, USA.
authors: C E
authors: CE
authors: Moffatt-Jauregui
authors: B
authors: B
authors: Robinson
authors: A V
authors: AV
authors: de Moya
authors: R D
authors: RD
authors: Brockman
authors: A V
authors: AV
authors: Roman
authors: M N
authors: MN
authors: Cash
authors: D J
authors: DJ
authors: Culp
authors: R J
authors: RJ
authors: Lamont
mesh_terms: D000328:Adult; D002452:Cell Count; D018929:Cell Culture Techniques; D002461:Cell Line, Transformed; D049109:Cell Proliferation; D048430:Cell Shape / Q000502:physiology; D016922:Cellular Senescence / Q000502:physiology; D004846:Epithelial Attachment / Q000166:cytology; D004847:Epithelial Cells / Q000166:cytology / Q000382:microbiology; D005881:Gingiva / Q000166:cytology* / Q000382:microbiology; D006801:Humans; D059785:Karyotype; D053535:Keratin-13 / Q000378:metabolism; D053547:Keratin-14 / Q000378:metabolism; D053539:Keratin-19 / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D063150:Polycomb Repressive Complex 1 / Q000235:genetics; D016966:Porphyromonas gingivalis / Q000502:physiology; D012190:Retroviridae / Q000235:genetics; D019098:Telomerase / Q000235:genetics; D016615:Telomere / Q000502:physiology; D051193:Toll-Like Receptors / Q000378:metabolism; D014161:Transduction, Genetic; D016335:Zinc Fingers / Q000235:genetics
chemical_list: C069077:BMI1 protein, human; D053535:Keratin-13; D053547:Keratin-14; D053539:Keratin-19; D051193:Toll-Like Receptors; D063150:Polycomb Repressive Complex 1; D019098:Telomerase
keywords: Porphyromonas gingivalis; bmi1; gingival epithelial cells; human telomerase reverse transcriptase; immortalization; telomerase