title: Trypsin-like protease-active extracellular protein extracts from Porphyromonas gingivalis ATCC 33277 induce apoptosis in bovine aortic endothelial cells.
abstract: OBJECTIVE
  Certain virulence factors participating in periodontitis may relate to cardiovascular diseases. This study was to evaluate the pro-apoptotic effect of protein extracts from Porphyromonas gingivalis on bovine aortic endothelial cells (BAECs).
  
  
  METHODS
  The BAECs were exposed to trypsin-like protease-active protein extracts from P. gingivalis, and apoptosis was examined by Hoechst 33342 staining, DNA fragmentation assay and cleaved caspase-3 detection. When BAECs were exposed to protein extracts pretreated with trypsin-like protease inhibitor (TLCK), the apoptosis rate was evaluated by Annexin V-propidium iodide staining. To further study the potential mechanism of the pro-apoptotic effect, immunoblotting was used to detect expression of alpha-tubulin, integrin beta1 and activated ERK1/2 in BAECs treated with protein extracts or cultured in suspension.
  
  
  RESULTS
  After exposure to the protein extracts, BAECs exhibited loss of cell adhesion and apoptotic cell death. The pro-apoptotic effect could be delayed by TLCK pretreatment. In addition, BAECs treated with protein extracts showed decreased levels of alpha-tubulin, integrin beta1 and activated ERK1/2. When BAECs were cultured in suspension, ERK1/2 activation was also inhibited, but the percentage decrease in ERK1/2 activation was less than that induced by protein extracts. Moreover, no significantly altered expression of alpha-tubulin was detected in suspended cells.
  
  
  CONCLUSIONS
  Trypsin-like protease-active protein extracts from P. gingivalis could induce apoptosis of BAECs. The destruction of alpha-tubulin and integrin beta1 and decrease of ERK1/2 activation might contribute to the pro-apoptotic effect of the protein extracts.
authors.affiliation: Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: N
authors.initials: N
authors.lastname: Tian
authors.forename: X Y
authors.initials: XY
authors.lastname: Ouyang
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects*; D017209:Apoptosis / Q000187:drug effects; D001426:Bacterial Proteins / Q000494:pharmacology*; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D019012:Integrin beta1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000201:enzymology*; D014357:Trypsin / Q000494:pharmacology*; D014361:Trypsin Inhibitors / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism; D037521:Virulence Factors / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D019012:Integrin beta1; D014361:Trypsin Inhibitors; D014404:Tubulin; D037521:Virulence Factors; D020928:Mitogen-Activated Protein Kinases; D014357:Trypsin