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Article
Activation of the phosphatidylinositol 3-kinase/Akt pathway contributes to survival of primary epithelial cells infected with the periodontal pathogen Porphyromonas gingivalis
Infection and Immunity
  • Özlem Yilmaz, University of Washington
  • Thomas Jungas, Université Paris
  • Philippe Verbeke, Université Paris
  • David M. Ojcius, University of California, Merced
ORCiD
David M. Ojcius: 0000-0003-1461-4495
Document Type
Article
DOI
10.1128/IAI.72.7.3743-3751.2004
Publication Date
7-1-2004
Abstract
Porphyromonas gingivalis, an important periodontal pathogen, infects primary gingival epithelial cells (GECs). Despite the large number of bacteria that replicate inside the GECs, the host cell remains viable. We demonstrate that P. gingivalis triggers rapid and reversible surface phosphatidylserine exposure through a mechanism requiring caspase activation. However, after 1 day of infection, the bacteria no longer induce phosphatidylserine externalization and instead protect infected cells against apoptosis. Infection exerts its effect at the level of mitochondria, as P. gingivalis also blocks depolarization of the mitochondrial transmembrane potential and cytochrome c release. Interestingly, protein kinase B/Akt is phosphorylated during infection, which can be blocked with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. Suppression of the PI3K/Akt pathway following staurosporine treatment results in mitochondrial-membrane depolarization, cytochrome c release, DNA fragmentation, and increased apoptosis of infected GECs. Thus, P. gingivalis stimulates early surface exposure of phosphatidylserine, which could downmodulate the inflammatory response, while also promoting host cell survival through the PI3K/Akt pathway.
Citation Information
Özlem Yilmaz, Thomas Jungas, Philippe Verbeke and David M. Ojcius. "Activation of the phosphatidylinositol 3-kinase/Akt pathway contributes to survival of primary epithelial cells infected with the periodontal pathogen Porphyromonas gingivalis" Infection and Immunity Vol. 72 Iss. 7 (2004) p. 3743 - 3751 ISSN: 0019-9567
Available at: http://works.bepress.com/david-ojcius/28/