Expression of the Streptococcus pneumoniae pilus-1 undergoes on and off switching during colonization in mice

Pancotto, Laura; Angelis, Gabriella De; Bizzarri, Esmeralda; Barocchi, Michèle A.; Giudice, Giuseppe Del; Moschioni, Monica; Ruggiero, Paolo

doi:10.1038/srep02040

Cited by 22 publications

(16 citation statements)

References 20 publications

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“…It is interesting that the expression of ebp pili and orthologous pili in other Gram-positive pathogens is tightly controlled (9). It has been suggested that a bistable switch mechanism may control the expression of streptococcal pili, such that individual cells are either "on" or "off" (29,30). An electron microscopic analysis of OG1RF suggests that a similar expression pattern may occur for ebp pili in OG1RF (7).…”

Section: Discussionmentioning

confidence: 99%

Expression of Adhesive Pili and the Collagen-Binding Adhesin Ace Is Activated by ArgR Family Transcription Factors in Enterococcus faecalis

Manias

Dunny

2018

J Bacteriol

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It was shown previously that the disruption of the gene encoding a predicted ArgR family transcription factor results in a severe defect in biofilm formation, as well as a significant attenuation of virulence of strain OG1RF in multiple experimental infection models. Using transcriptome sequencing (RNA-seq), we observed-dependent changes in the expression of more than 20 genes. AhrC-repressed genes included predicted determinants of arginine catabolism and several other metabolic genes and predicted transporters, while AhrC-activated genes included determinants involved in the production of surface protein adhesins. Most notably, the structural and regulatory genes of the locus encoding adhesive pili were positively regulated, as well as the gene, encoding a collagen-binding adhesin. Using transcription reporter fusions, we determined that and a second transcription factor gene,, both function to activate the expression of , which directly activates the transcription of the pilus structural genes. Our data suggest that in the wild-type, the low levels of EbpR limit the expression of pili and that biofilm biomass is also limited by the amount of pili expressed by the bacteria. The expression of is similarly enhanced by AhrC and ArgR2, but expression is not dependent on EbpR. Our results demonstrate the existence of novel regulatory cascades controlled by a pair of ArgR family transcription factors that might function as a heteromeric protein complex. Cell surface adhesins play critical roles in the formation of biofilms, host colonization, and the pathogenesis of opportunistic infections by Here, we present new results showing that the expression of two major enterococcal surface adhesins, pili, and the collagen-binding protein Ace is positively regulated at the transcription level by two family transcription factors, AhrC and ArgR2. In the case of pili, the direct target of regulation is the gene, previously shown to activate the transcription of the pilus structural genes, while the activation of transcription appears to be directly impacted by the two ArgR proteins. These transcription factors may represent new targets for blocking enterococcal infections.

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Section: Discussionmentioning

confidence: 99%

Expression of Adhesive Pili and the Collagen-Binding Adhesin Ace Is Activated by ArgR Family Transcription Factors in Enterococcus faecalis

Manias

Dunny

2018

J Bacteriol

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“… Pili : these hair-like structures are located on the cell surface of S. pneumoniae and many other bacteria ( 27 , 51 , 81 ). They assist with S. pneumoniae’s attachment and colonization of epithelial cells within the nasopharynx and lungs of hosts ( 51 , 81 , 82 ). These pili also help the bacteria avoid phagocytosis by host immune cells ( 22 ).…”

Section: Virulence Factorsmentioning

confidence: 99%

Streptococcus pneumoniae’s Virulence and Host Immunity: Aging, Diagnostics, and Prevention

2018

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Streptococcus pneumoniae is an infectious pathogen responsible for millions of deaths worldwide. Diseases caused by this bacterium are classified as pneumococcal diseases. This pathogen colonizes the nasopharynx of its host asymptomatically, but overtime can migrate to sterile tissues and organs and cause infections. Pneumonia is currently the most common pneumococcal disease. Pneumococcal pneumonia is a global health concern and vastly affects children under the age of five as well as the elderly and individuals with pre-existing health conditions. S. pneumoniae has a large selection of virulence factors that promote adherence, invasion of host tissues, and allows it to escape host immune defenses. A clear understanding of S. pneumoniae’s virulence factors, host immune responses, and examining the current techniques available for diagnosis, treatment, and disease prevention will allow for better regulation of the pathogen and its diseases. In terms of disease prevention, other considerations must include the effects of age on responses to vaccines and vaccine efficacy. Ongoing work aims to improve on current vaccination paradigms by including the use of serotype-independent vaccines, such as protein and whole cell vaccines. Extending our knowledge of the biology of, and associated host immune response to S. pneumoniae is paramount for our improvement of pneumococcal disease diagnosis, treatment, and improvement of patient outlook.

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“…However, ectopic expression of FHA during the Bvg − phase was not sufficient to promote adherence in vivo (20), underscoring the importance of tight control over adhesin expression for effective colonization. Similarly, pilus expression in pneumococci appears to be regulated, as it peaks during the early phases of murine colonization (86). …”

Section: Acquisition and Attachmentmentioning

confidence: 99%

Mechanisms of Bacterial Colonization of the Respiratory Tract

Siegel¹,

Weiser²

2015

Annu. Rev. Microbiol.

154

123

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Respiratory tract infections are an important cause of morbidity and mortality worldwide. Chief among these are infections involving the lower airways. The opportunistic bacterial pathogens responsible for most cases of pneumonia can cause a range of local and invasive infections. However, bacterial colonization (or carriage) in the upper airway is the prerequisite of all these infections. Successful colonizers must attach to the epithelial lining, grow on the nutrient-limited mucosal surface, evade the host immune response, and transmit to a susceptible host. Here, we review the molecular mechanisms underlying these conserved stages of carriage. We also examine how the demands of colonization influence progression to disease. A range of bacteria can colonize the upper airway; nevertheless, we focus on strategies shared by many respiratory tract opportunistic pathogens. Understanding colonization opens a window to the evolutionary pressures these pathogens face within their animal hosts and that have selected for attributes that contribute to virulence and pathogenesis.

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Expression of the Streptococcus pneumoniae pilus-1 undergoes on and off switching during colonization in mice

Cited by 22 publications

References 20 publications

Expression of Adhesive Pili and the Collagen-Binding Adhesin Ace Is Activated by ArgR Family Transcription Factors in Enterococcus faecalis

Expression of Adhesive Pili and the Collagen-Binding Adhesin Ace Is Activated by ArgR Family Transcription Factors in Enterococcus faecalis

Streptococcus pneumoniae’s Virulence and Host Immunity: Aging, Diagnostics, and Prevention

Mechanisms of Bacterial Colonization of the Respiratory Tract

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