Inhibition of the ULK1 protein complex suppresses Staphylococcus-induced autophagy and cell death

Ohood A. Radhi, Scott Davidson, Fiona Scott, Run X. Zeng, D. Heulyn Jones, Nicholas C. O. Tomkinson, Jun Yu, Edmond Y.W. Chan

Research output: Contribution to journalArticle

Abstract

Autophagy plays multiple roles in host cells challenged with extracellular pathogens. Here, we aimed to explore whether autophagy inhibition could prevent bacterial infections. We first confirmed widely distinct patterns of autophagy responses in host cells infected with Staphylococcus aureus, as compared with Salmonella. Only infection with Staphylococcus produced strong accumulation of lipidated autophagy-related protein LC3B (LC3B-II). Infection with virulent Staphylococcus strains induced formation of p62-positive aggregates, suggestive of accumulated ubiquitinated targets. During Salmonella infection, bacteria remain enclosed by lysosomal-associated membrane protein 2 (LAMP2)-positive lysosomes, whereas virulent Staphylococcus apparently exited from enlarged lysosomes and invaded the cytoplasm. Surprisingly, Staphylococcus appeared to escape from the lysosome without generation of membrane-damage signals as detected by Galectin3 recruitment. In contrast, Salmonella infection produced high levels of lysosomal damage, consistent with a downstream antibacterial xenophagy response. Lastly, we studied the Unc-51-like autophagy-activating kinase 1 (ULK1) regulatory complex, including the essential subunit autophagy-related protein 13 (ATG13). Infection of cells with either Staphylococcus or Salmonella led to recruitment of ATG13 to sites of cytosolic bacterial cells to promote autophagosome formation. Of note, genetic targeting of ATG13 suppressed autophagy and the ability of Staphylococcus to infect and kill host cells. Two different ULK1 inhibitors also prevented Staphylococcus intracellular replication and host cell death. Interestingly, inhibition of the ULK1 pathway had the opposite effect on Salmonella, sensitizing cells to the infection. Our results suggest that ULK1 inhibitors may offer a potential strategy to impede cellular infection by Staphylococcus aureus.
LanguageEnglish
Number of pages19
JournalJournal of Biological Chemistry
Volume294
Early online date6 Aug 2019
DOIs
Publication statusE-pub ahead of print - 6 Aug 2019

Fingerprint

Salmonella
Autophagy
Cell death
Staphylococcus
Cell Death
Phosphotransferases
Lysosomes
Proteins
Lysosomal-Associated Membrane Protein 2
Infection
Salmonella Infections
Staphylococcus aureus
Pathogens
Bacteria
Cells
Autophagy-Related Protein-1 Homolog
Bacterial Infections
Membranes
Cytoplasm
Autophagy-Related Proteins

Keywords

  • autophagy
  • Unc-51-like autophagy-activating kinase 1 (ULK1) ,
  • Salmonella Typhimurium
  • Staphylococcus aureus

Cite this

Radhi, Ohood A. ; Davidson, Scott ; Scott, Fiona ; Zeng, Run X. ; Jones, D. Heulyn ; Tomkinson, Nicholas C. O. ; Yu, Jun ; Chan, Edmond Y.W. / Inhibition of the ULK1 protein complex suppresses Staphylococcus-induced autophagy and cell death. In: Journal of Biological Chemistry. 2019 ; Vol. 294.
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abstract = "Autophagy plays multiple roles in host cells challenged with extracellular pathogens. Here, we aimed to explore whether autophagy inhibition could prevent bacterial infections. We first confirmed widely distinct patterns of autophagy responses in host cells infected with Staphylococcus aureus, as compared with Salmonella. Only infection with Staphylococcus produced strong accumulation of lipidated autophagy-related protein LC3B (LC3B-II). Infection with virulent Staphylococcus strains induced formation of p62-positive aggregates, suggestive of accumulated ubiquitinated targets. During Salmonella infection, bacteria remain enclosed by lysosomal-associated membrane protein 2 (LAMP2)-positive lysosomes, whereas virulent Staphylococcus apparently exited from enlarged lysosomes and invaded the cytoplasm. Surprisingly, Staphylococcus appeared to escape from the lysosome without generation of membrane-damage signals as detected by Galectin3 recruitment. In contrast, Salmonella infection produced high levels of lysosomal damage, consistent with a downstream antibacterial xenophagy response. Lastly, we studied the Unc-51-like autophagy-activating kinase 1 (ULK1) regulatory complex, including the essential subunit autophagy-related protein 13 (ATG13). Infection of cells with either Staphylococcus or Salmonella led to recruitment of ATG13 to sites of cytosolic bacterial cells to promote autophagosome formation. Of note, genetic targeting of ATG13 suppressed autophagy and the ability of Staphylococcus to infect and kill host cells. Two different ULK1 inhibitors also prevented Staphylococcus intracellular replication and host cell death. Interestingly, inhibition of the ULK1 pathway had the opposite effect on Salmonella, sensitizing cells to the infection. Our results suggest that ULK1 inhibitors may offer a potential strategy to impede cellular infection by Staphylococcus aureus.",
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Inhibition of the ULK1 protein complex suppresses Staphylococcus-induced autophagy and cell death. / Radhi, Ohood A.; Davidson, Scott; Scott, Fiona; Zeng, Run X.; Jones, D. Heulyn ; Tomkinson, Nicholas C. O. ; Yu, Jun; Chan, Edmond Y.W.

In: Journal of Biological Chemistry, Vol. 294, 06.08.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Inhibition of the ULK1 protein complex suppresses Staphylococcus-induced autophagy and cell death

AU - Radhi, Ohood A.

AU - Davidson, Scott

AU - Scott, Fiona

AU - Zeng, Run X.

AU - Jones, D. Heulyn

AU - Tomkinson, Nicholas C. O.

AU - Yu, Jun

AU - Chan, Edmond Y.W.

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AB - Autophagy plays multiple roles in host cells challenged with extracellular pathogens. Here, we aimed to explore whether autophagy inhibition could prevent bacterial infections. We first confirmed widely distinct patterns of autophagy responses in host cells infected with Staphylococcus aureus, as compared with Salmonella. Only infection with Staphylococcus produced strong accumulation of lipidated autophagy-related protein LC3B (LC3B-II). Infection with virulent Staphylococcus strains induced formation of p62-positive aggregates, suggestive of accumulated ubiquitinated targets. During Salmonella infection, bacteria remain enclosed by lysosomal-associated membrane protein 2 (LAMP2)-positive lysosomes, whereas virulent Staphylococcus apparently exited from enlarged lysosomes and invaded the cytoplasm. Surprisingly, Staphylococcus appeared to escape from the lysosome without generation of membrane-damage signals as detected by Galectin3 recruitment. In contrast, Salmonella infection produced high levels of lysosomal damage, consistent with a downstream antibacterial xenophagy response. Lastly, we studied the Unc-51-like autophagy-activating kinase 1 (ULK1) regulatory complex, including the essential subunit autophagy-related protein 13 (ATG13). Infection of cells with either Staphylococcus or Salmonella led to recruitment of ATG13 to sites of cytosolic bacterial cells to promote autophagosome formation. Of note, genetic targeting of ATG13 suppressed autophagy and the ability of Staphylococcus to infect and kill host cells. Two different ULK1 inhibitors also prevented Staphylococcus intracellular replication and host cell death. Interestingly, inhibition of the ULK1 pathway had the opposite effect on Salmonella, sensitizing cells to the infection. Our results suggest that ULK1 inhibitors may offer a potential strategy to impede cellular infection by Staphylococcus aureus.

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KW - Salmonella Typhimurium

KW - Staphylococcus aureus

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SN - 0021-9258

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