<it>Staphylococcus aureus</it> - induced tumor necrosis factor - related apoptosis - inducing ligand expression mediates apoptosis and caspase-8 activation in infected osteoblasts

• Main Authors: Bost Kenneth L, Anguita Juan, Marriott Ian, Rivera F, Alexander Emily H, Hudson Michael C
• Format: Article
• Language: English
• Published: BMC 2003-04-01
• Series: BMC Microbiology
• Online Access: http://www.biomedcentral.com/1471-2180/3/5

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus aureus </it>infection of normal osteoblasts induces expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).</p> <p>Results</p> <p>Normal osteoblasts were incubated in the presence of purified bacterial products over a range of concentrations. Results demonstrate that purified surface structures and a selected superantigen present in the extracellular environment are not capable of inducing TRAIL expression by osteoblasts. Osteoblasts were co-cultured with <it>S. aureus </it>at various multiplicities of infection utilizing cell culture chamber inserts. Results of those experiments suggest that direct contact between bacteria and osteoblasts is necessary for optimal TRAIL induction. Finally, <it>S. aureus </it>infection of osteoblasts in the presence of anti-TRAIL antibody demonstrates that TRAIL mediates caspase-8 activation and apoptosis of infected cells.</p> <p>Conclusions</p> <p>Collectively, these findings suggest a mechanism whereby <it>S. aureus </it>mediates bone destruction via induction of osteoblast apoptosis.</p>