Eliminating Legionella by inhibiting BCL-XL to induce macrophage apoptosis

Mary Speir, Kate E. Lawlor, Stefan P. Glaser, Gilu Abraham, Seong Chow, Adam Vogrin, Keith E. Schulze, Ralf Schuelein, Lorraine A. O'Reilly, Kylie Mason, Elizabeth L. Hartland, Trevor Lithgow, Andreas Strasser, Guillaume Lessene, David C. S. Huang, James E. Vince, Thomas Naderer

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34 Citations (Scopus)


Human pathogenic Legionella replicate in alveolar macrophages and cause a potentially lethal form of pneumonia known as Legionnaires' disease 1. Here, we have identified a host-directed therapeutic approach to eliminate intracellular Legionella infections. We demonstrate that the genetic deletion, or pharmacological inhibition, of the host cell pro-survival protein BCL-XL induces intrinsic apoptosis of macrophages infected with virulent Legionella strains, thereby abrogating Legionella replication. BCL-XL is essential for the survival of Legionella-infected macrophages due to bacterial inhibition of host-cell protein synthesis, resulting in reduced levels of the short-lived, related BCL-2 pro-survival family member, MCL-1. Consequently, a single dose of a BCL-XL-targeted BH3-mimetic therapy, or myeloid cell-restricted deletion of BCL-XL, limits Legionella replication and prevents lethal lung infections in mice. These results indicate that repurposing BH3-mimetic compounds, originally developed to induce cancer cell apoptosis, may have efficacy in treating Legionnaires' and other diseases caused by intracellular microbes.

Original languageEnglish
Article number15034
Number of pages9
JournalNature Microbiology
Issue number3
Publication statusPublished - 24 Feb 2016


  • apoptosis
  • bacterial pathogenesis
  • immune cell death
  • pathogens

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