<named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System
ABSTRACT The gut microbiota can significantly impact invading pathogens and the disease they cause; however, many of the mechanisms that dictate commensal-pathogen interactions remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a potentially lethal human intestinal pathogen that uses micro...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2019-12-01
|
| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mBio.02547-19 |
| _version_ | 1818997477652561920 |
|---|---|
| author | Elizabeth A. Cameron Vanessa Sperandio Gary M. Dunny |
| author_facet | Elizabeth A. Cameron Vanessa Sperandio Gary M. Dunny |
| author_sort | Elizabeth A. Cameron |
| collection | DOAJ |
| description | ABSTRACT The gut microbiota can significantly impact invading pathogens and the disease they cause; however, many of the mechanisms that dictate commensal-pathogen interactions remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a potentially lethal human intestinal pathogen that uses microbiota-derived molecules as cues to efficiently regulate virulence factor expression. Here, we investigate the interaction between EHEC and Enterococcus faecalis, a common human gut commensal, and show that E. faecalis affects both expression and activity of the EHEC type III secretion system (T3SS) via two distinct mechanisms. First, in the presence of E. faecalis there is increased transcription of genes encoding the EHEC T3SS. This leads to increased effector translocation and ultimately greater numbers of pedestals formed on host cells. The same effect was observed with several strains of enterococci, suggesting that it is a general characteristic of this group. In a mechanism separate from E. faecalis-induced transcription of the T3SS, we report that an E. faecalis-secreted protease, GelE, cleaves a critical structural component of the EHEC T3SS, EspB. Our data suggest that this cleavage actually increases effector translocation by the T3SS, supporting a model where EspB proteolysis promotes maximum T3SS activity. Finally, we report that treatment of EHEC with E. faecalis-conditioned cell-free medium is insufficient to induce increased T3SS expression, suggesting that this effect relies on cell contact between E. faecalis and EHEC. This work demonstrates a complex interaction between a human commensal and pathogen that impacts both expression and function of a critical virulence factor. IMPORTANCE This work reveals a complex and multifaceted interaction between a human gut commensal, Enterococcus faecalis, and a pathogen, enterohemorrhagic E. coli. We demonstrate that E. faecalis enhances expression of the enterohemorrhagic E. coli type III secretion system and that this effect likely depends on cell contact between the commensal and the pathogen. Additionally, the GelE protease secreted by E. faecalis cleaves a critical structural component of the EHEC type III secretion system. In agreement with previous studies, we find that this cleavage actually increases effector protein delivery into host cells by the secretion system. This work demonstrates that commensal bacteria can significantly shape expression and activity of pathogen virulence factors, which may ultimately shape the progression of disease. |
| first_indexed | 2024-12-20T21:46:16Z |
| format | Article |
| id | doaj.art-e4911504ab2241fb9dd1ac20419234e0 |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-12-20T21:46:16Z |
| publishDate | 2019-12-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-e4911504ab2241fb9dd1ac20419234e02022-12-21T19:25:40ZengAmerican Society for MicrobiologymBio2150-75112019-12-0110610.1128/mBio.02547-19<named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion SystemElizabeth A. Cameron0Vanessa Sperandio1Gary M. Dunny2Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USADepartment of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USADepartment of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USAABSTRACT The gut microbiota can significantly impact invading pathogens and the disease they cause; however, many of the mechanisms that dictate commensal-pathogen interactions remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a potentially lethal human intestinal pathogen that uses microbiota-derived molecules as cues to efficiently regulate virulence factor expression. Here, we investigate the interaction between EHEC and Enterococcus faecalis, a common human gut commensal, and show that E. faecalis affects both expression and activity of the EHEC type III secretion system (T3SS) via two distinct mechanisms. First, in the presence of E. faecalis there is increased transcription of genes encoding the EHEC T3SS. This leads to increased effector translocation and ultimately greater numbers of pedestals formed on host cells. The same effect was observed with several strains of enterococci, suggesting that it is a general characteristic of this group. In a mechanism separate from E. faecalis-induced transcription of the T3SS, we report that an E. faecalis-secreted protease, GelE, cleaves a critical structural component of the EHEC T3SS, EspB. Our data suggest that this cleavage actually increases effector translocation by the T3SS, supporting a model where EspB proteolysis promotes maximum T3SS activity. Finally, we report that treatment of EHEC with E. faecalis-conditioned cell-free medium is insufficient to induce increased T3SS expression, suggesting that this effect relies on cell contact between E. faecalis and EHEC. This work demonstrates a complex interaction between a human commensal and pathogen that impacts both expression and function of a critical virulence factor. IMPORTANCE This work reveals a complex and multifaceted interaction between a human gut commensal, Enterococcus faecalis, and a pathogen, enterohemorrhagic E. coli. We demonstrate that E. faecalis enhances expression of the enterohemorrhagic E. coli type III secretion system and that this effect likely depends on cell contact between the commensal and the pathogen. Additionally, the GelE protease secreted by E. faecalis cleaves a critical structural component of the EHEC type III secretion system. In agreement with previous studies, we find that this cleavage actually increases effector protein delivery into host cells by the secretion system. This work demonstrates that commensal bacteria can significantly shape expression and activity of pathogen virulence factors, which may ultimately shape the progression of disease.https://journals.asm.org/doi/10.1128/mBio.02547-19commensal pathogen interactiongut microbiomevirulence regulationEHECbacterial communication |
| spellingShingle | Elizabeth A. Cameron Vanessa Sperandio Gary M. Dunny <named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System mBio commensal pathogen interaction gut microbiome virulence regulation EHEC bacterial communication |
| title | <named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System |
| title_full | <named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System |
| title_fullStr | <named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System |
| title_full_unstemmed | <named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System |
| title_short | <named-content content-type="genus-species">Enterococcus faecalis</named-content> Enhances Expression and Activity of the Enterohemorrhagic <named-content content-type="genus-species">Escherichia coli</named-content> Type III Secretion System |
| title_sort | named content content type genus species enterococcus faecalis named content enhances expression and activity of the enterohemorrhagic named content content type genus species escherichia coli named content type iii secretion system |
| topic | commensal pathogen interaction gut microbiome virulence regulation EHEC bacterial communication |
| url | https://journals.asm.org/doi/10.1128/mBio.02547-19 |
| work_keys_str_mv | AT elizabethacameron namedcontentcontenttypegenusspeciesenterococcusfaecalisnamedcontentenhancesexpressionandactivityoftheenterohemorrhagicnamedcontentcontenttypegenusspeciesescherichiacolinamedcontenttypeiiisecretionsystem AT vanessasperandio namedcontentcontenttypegenusspeciesenterococcusfaecalisnamedcontentenhancesexpressionandactivityoftheenterohemorrhagicnamedcontentcontenttypegenusspeciesescherichiacolinamedcontenttypeiiisecretionsystem AT garymdunny namedcontentcontenttypegenusspeciesenterococcusfaecalisnamedcontentenhancesexpressionandactivityoftheenterohemorrhagicnamedcontentcontenttypegenusspeciesescherichiacolinamedcontenttypeiiisecretionsystem |