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Involvement of caspases in apoptotic cell death of murine macrophages infected with Actinobacillus actinomycetemcomitans
Author(s) -
aka Koji,
Ishisaki Akira,
Okahashi Nobuo,
Koseki Takeyoshi,
Kato Satsuki,
Muro Miyuki,
Nakashima Keisuke,
Nishihara Tatsuji,
Kowashi Yusuke
Publication year - 2001
Publication title -
journal of periodontal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.31
H-Index - 83
eISSN - 1600-0765
pISSN - 0022-3484
DOI - 10.1034/j.1600-0765.2001.00613.x
Subject(s) - apoptosis , caspase , programmed cell death , biology , caspase 3 , cell culture , caspase 1 , microbiology and biotechnology , secretion , biochemistry , genetics
Infection of murine macrophages in vitro with periodontopathic bacterium Actinobacillus actinomycetemcomitans induces apoptotic cell death. In this study, we investigated the involvement of caspases in apoptotic cell death of A. actinomycetemcomitans ‐infected macrophages. Two peptide inhibitors of caspases, benzyloxycarbonyl‐Val‐Ala‐Asp (OMe)‐fluoromethyl ketone (Z‐VAD‐FMK) and benzyloxycarbonyl‐Asp‐Glu‐Val‐Asp (OMe)‐fluoromethyl ketone (Z‐DEVD‐FMK), inhibited apoptotic cell death of murine macrophage cell line J774.1 infected with A. actinomycetemcomitans . During the process of apoptosis, interleukin‐1β(IL‐1β) was detected in the culture supernatants of J774.1 cells. IL‐1β secretion was blocked by the caspase‐1 inhibitor, Z‐VAD‐FMK, indicating that caspase‐1 is involved in not only the induction of apoptosis but also the IL‐1β secretion from A. actinomycetemcomitans ‐infected J774.1 cells. Immunoblot analysis revealed that the infection of A. actinomycetemcomitans to J774.1 cells induced the cleavage of retinoblastoma protein (Rb), suggesting that caspase‐3 was activated by A. actinomycetemcomitans infection. The cytosol from A. actinomycetemcomitans ‐infected J774.1 cells induced Rb proteolysis in vitro , which was inhibited by the caspase‐3 inhibitor, Z‐DEVD‐FMK. Furthermore, caspase‐3‐like activity was markedly increased in J774.1 cells infected with A. actinomycetemcomitans between 12 h and 24 h, which was subsequently inhibited by the addition of caspase‐3 inhibitor, Z‐DEVD‐FMK. These findings indicate that caspase‐3 induces apoptosis in J774.1 cells infected with A. actinomycetemcomitans . Taken together, these results suggest that caspase‐1 and caspase‐3 are involved in the induction of apoptosis in A. actinomycetemcomitans ‐infected macrophages.