Papers In Press, published online ahead of print November 29, 2006
J. Biol. Chem, 10.1074/jbc.M609784200
Submitted on October 17, 2006
Revised on November 14, 2006
Accepted on November 28, 2006
Staphylococcus aureus subvert autophagy for induction of caspase-independent host cell death
Annabelle Schnaith, Hamid Kashkar, Sonja Leggio, Klaus Addicks, Martin Krönke, and Oleg Krut
Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne 50935
Corresponding Author: oleg.krut{at}uni-koeln.de
Staphylococcus aureus is a common bacterial etiology of serious infectious diseases. S. aureus can invade various types of non-professional phagocytes to produce host cell death. We show here that shortly after invasion of HeLa cells, S. aureus transit to autophagosomes characterized by double membranes and co-localization with LC3. S. aureus were not able to replicate in, and produce cell death of, autophagy-deficient, atg5-/- mouse embryonic fibroblasts. S. aureus-containing autophagosomes do not acidify nor do they acquire LAMP-2, indicating that S. aureus inhibits autophagosome maturation and fusion with lysosomes. Eventually, S. aureus escape from autophagosomes into the cytoplasm, which results in caspase-independent host cell death. S. aureus strains deficient for agr, a global regulator of S. aureus virulence, were not targeted by autophagy and did not produce host-cell death. Autophagy induction by rapamycin restored both replication and cytotoxicity of agr-deficient S. aureus strains, indicating that agr-regulated factor(s) are required for autophagy-mediated cytotoxicity. The results of this study suggest that rapid induction of autophagy is essential for S. aureus replication, escape into the cytoplasm and host cell killing.