title: The upregulation of receptor activator NF-kappaB ligand expression by interleukin-1alpha and Porphyromonas endodontalis in human osteoblastic cells.
abstract: OBJECTIVE
  To investigate the receptor activator of nuclear factor-kappa B (NF-kappaB) ligand (RANKL) in osteoblastic cells stimulated with inflammatory mediators.
  
  
  METHODS
  The expression of RANKL in human osteoblastic cell line U2OS stimulated by pro-inflammatory cytokine interleukin (IL)-1alpha and black-pigmented bacteria Porphyromonas endodontalis was investigated by Western blot and enzyme-linked immunosorbent assay (ELISA). The significance of the results obtained from control and treated groups was statistically analysed by the paired Student's t-test.
  
  
  RESULTS
  IL-1alpha was found to upregulate RANKL production in U2OS cells (P < 0.05). Investigations of the time dependence of RANKL expression in IL-1alpha-treated cells revealed a rapid accumulation of RANKL protein after 1 h of exposure; it remained elevated throughout the 24-h incubation period shown by Western blot and ELISA. In addition, P. endodontalis also increased RANKL expression in U2OS cells after 4-h incubation period demonstrated by Western blot and ELISA (P < 0.05).
  
  
  CONCLUSIONS
  IL-1alpha and P. endodontalis may be involved in developing apical periodontitis through the stimulation of RANKL production.
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: S-C
authors.initials: SC
authors.lastname: Chen
authors.forename: F-M
authors.initials: FM
authors.lastname: Huang
authors.forename: S-S
authors.initials: SS
authors.lastname: Lee
authors.forename: M-Z
authors.initials: MZ
authors.lastname: Li
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chang
mesh_terms: D016301:Alveolar Bone Loss / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D053582:Interleukin-1alpha / Q000378:metabolism* / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D010485:Periapical Periodontitis / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D045202:Porphyromonas endodontalis / Q000737:chemistry*; D053245:RANK Ligand / Q000032:analysis / Q000096:biosynthesis*; D015854:Up-Regulation
chemical_list: D017077:Culture Media, Conditioned; D018836:Inflammation Mediators; D053582:Interleukin-1alpha; D053245:RANK Ligand