Role of CD14 molecules in internalization of Actinobacillus actinomycetemcomitans by macrophages and subsequent induction of apoptosis

Miyuki Muro, Takeyoshi Koseki, Sumio Akifusa, Satsuki Kato, Yusuke Kowashi, Yasuyoshi Ohsaki, Kenji Yamato, Masahiro Nishijima, Tatsuji Nishihara

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Abstract

We report the evidence for apoptosis in J774.1 cells by the periodontopathic bacterium Actinobacillus actinomycetemcomitans, suggesting that the ability of A. actinomycetemcomitans to promote apoptosis might be important in the initiation and development of periodontitis. In this study, we examined the role of macrophage CD14, anchored by a glycerophosphatidylinositol tail, in the induction of apoptosis by A.actinomycetemcomitans infection by using the parent J774.1 cells and CD14- defective mutant (LR-9) cells. A small number of A. actinomycetemcomitans Y4 cells inside the LR-9 cells compared with the number in J774.1 cells was detected by confocal scanning microscopy. We found that LR-9 cells showed a weak cytotoxic effect after being infected with A. actinomycetemcomitans Y4. Apoptotic cell death of LR-9 cells infected with A. actinomycetemcomitans Y4, compared with that of the parent J774.1 cells was almost undetectable, as shown by the proportion of fragmented DNA in agarose gel electrophoresis and by the terminal deoxynucleotidyl transferase-mediated dUTP end-labeling method. Flow cytometric cell cycle analysis of J774.1 cells infected with A. actinomycetemcomitans Y4 revealed the increased percentage of apoptotic cells with hypodiploid DNA. However, LR-9 cells infected with A. actinomycetemcomitans Y4 showed no increase in population of apoptotic nuclei compared with the noninfected cells. These findings suggest that the CD14 molecules may contribute to the phagocytosis of A. actinomycetemcomitans by J774.1 cells and regulate, at least in part, apoptotic cell death of macrophages infected with A. actinomycetemcomitans.

Original languageEnglish
Pages (from-to)1147-1151
Number of pages5
JournalInfection and Immunity
Volume65
Issue number4
Publication statusPublished - Apr 15 1997

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All Science Journal Classification (ASJC) codes

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

Cite this

Muro, M., Koseki, T., Akifusa, S., Kato, S., Kowashi, Y., Ohsaki, Y., ... Nishihara, T. (1997). Role of CD14 molecules in internalization of Actinobacillus actinomycetemcomitans by macrophages and subsequent induction of apoptosis. Infection and Immunity, 65(4), 1147-1151.