The aminoglycoside resistance-promoting AmgRS envelope stress-responsive two-component system in Pseudomonas aeruginosa is zinc-activated and protects cells from zinc-promoted membrane damage

Poole, Keith; Hay, Thomas J. M.; Gilmour, C. M.; Fruci, Michael

doi:10.1099/mic.0.000787

Cited by 13 publications

(8 citation statements)

References 70 publications

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“…In AZM treated biofilms, we observed reduced transcript levels of several global gene expression modulators associated with stress responses (rpoS [70,71], rpoH [72], and relA [73]), anaerobic metabolism (anr [74,75]), virulence and biofilm formation (rsmY [76]), amino acid and nitrogen metabolism (argR [77]), ntrBC and gdhB [78]), QS (vqsR [79]), and antibiotic resistance (amgR [80]) (Fig 2D). The expression of stress, virulence, biofilm, motility, and metabolism-related genes, many of which are controlled by these regulators, were also downregulated.…”

Section: The Effects Of Azm On P Aeruginosa Gene Expressionmentioning

confidence: 95%

Quantitative mapping of mRNA 3’ ends in Pseudomonas aeruginosa reveals a pervasive role for premature 3’ end formation in response to azithromycin

et al. 2021

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Pseudomonas aeruginosa produces serious chronic infections in hospitalized patients and immunocompromised individuals, including patients with cystic fibrosis. The molecular mechanisms by which P. aeruginosa responds to antibiotics and other stresses to promote persistent infections may provide new avenues for therapeutic intervention. Azithromycin (AZM), an antibiotic frequently used in cystic fibrosis treatment, is thought to improve clinical outcomes through a number of mechanisms including impaired biofilm growth and quorum sensing (QS). The mechanisms underlying the transcriptional response to AZM remain unclear. Here, we interrogated the P. aeruginosa transcriptional response to AZM using a fast, cost-effective genome-wide approach to quantitate RNA 3’ ends (3pMap). We also identified hundreds of P. aeruginosa genes with high incidence of premature 3’ end formation indicative of riboregulation in their transcript leaders using 3pMap. AZM treatment of planktonic and biofilm cultures alters the expression of hundreds of genes, including those involved in QS, biofilm formation, and virulence. Strikingly, most genes downregulated by AZM in biofilms had increased levels of intragenic 3’ ends indicating premature transcription termination, transcriptional pausing, or accumulation of stable intermediates resulting from the action of nucleases. Reciprocally, AZM reduced premature intragenic 3’ end termini in many upregulated genes. Most notably, reduced termination accompanied robust induction of obgE, a GTPase involved in persister formation in P. aeruginosa. Our results support a model in which AZM-induced changes in 3’ end formation alter the expression of central regulators which in turn impairs the expression of QS, biofilm formation and stress response genes, while upregulating genes associated with persistence.

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Section: The Effects Of Azm On P Aeruginosa Gene Expressionmentioning

confidence: 95%

Quantitative mapping of mRNA 3’ ends in Pseudomonas aeruginosa reveals a pervasive role for premature 3’ end formation in response to azithromycin

et al. 2021

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“…Zinc is an essential micronutrient for all organisms, serves as a structural or catalytic cofactor in 5 to 6% of proteins in the bacterial proteome (22)(23)(24), and can play an important role in the expression of key virulence factors (25)(26)(27)(28)(29)(30)(31)(32). However, high concentrations of zinc are toxic, possibly due to competition with other relevant metal ions (24,33), inhibition of key enzymes and essential metabolic reactions in the cell (32,34,35), and/or induction of membrane stress (36). For most pathogens, there is intense competition for zinc in the face of the host's nutritional immunity defense mechanisms (37) and, conversely, elevating zinc levels is also a strategy used by macrophages to kill pathogens encapsulated in their phagosomes (38,39).…”

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confidence: 99%

Availability of Zinc Impacts Interactions between Streptococcus sanguinis and Pseudomonas aeruginosa in Coculture

Gifford

Hampton

et al. 2020

J Bacteriol

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Airway infections associated with cystic fibrosis (CF) are polymicrobial. We reported previously that clinical isolates of Pseudomonas aeruginosa promote the growth of a variety of streptococcal species. To explore the mechanistic basis of this interaction, we performed a genetic screen to identify mutants of Streptococcus sanginuis SK36 whose growth was no longer enhanced by P. aeruginosa PAO1. Mutations in the zinc uptake systems of S. sanguinis SK36 reduced growth of these strains by 1 to 3 logs compared to that of wild-type S. sanguinis SK36 when grown in coculture with P. aeruginosa PAO1, and exogenous zinc (0.1 to 10 μM) rescued the coculture defect of zinc uptake mutants of S. sanguinis SK36. Zinc uptake mutants of S. sanguinis SK36 had no obvious growth defect in monoculture. Consistent with competition for zinc driving coculture dynamics, S. sanguinis SK36 grown in coculture with P. aeruginosa showed increased expression of zinc uptake genes compared to that of S. sanguinis grown alone. Strains of P. aeruginosa PAO1 defective in zinc transport also supported ∼2-fold more growth by S. sanguinis compared to that in coculture with wild-type P. aeruginosa PAO1. An analysis of 118 CF sputum samples revealed that total zinc levels varied from ∼5 to 145 μM. At relatively low zinc levels, Pseudomonas and Streptococcus spp. were found in approximately equal abundance; at higher zinc levels, we observed a decline in relative abundance of Streptococcus spp., perhaps as a result of increasing zinc toxicity. Together, our data indicate that the relative abundances of these microbes in the CF airway may be impacted by zinc levels. IMPORTANCE Polymicrobial infections in CF cases likely impact patient health, but the mechanism(s) underlying such interactions is poorly understood. Here, we show using an in vitro model system that interactions between Pseudomonas and Streptococcus are modulated by zinc availability, and clinical data are consistent with this model. Together with previous studies, our work supports a role for metal homeostasis as a key factor driving microbial interactions.

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“…In AZM treated biofilms (Figure 2D), we observed reduced transcript levels of several global gene expression modulators associated with stress responses ( rpoS [70, 71] , rpoH [72], and relA [73]), anaerobic metabolism ( anr [74, 75]), virulence and biofilm formation ( rsmY [76]), amino acid and nitrogen metabolism ( argR [77]), ntrBC and gdhB [78]), QS ( vqsR [79]), and antibiotic resistance (amgR [80]) (Figure 3D). The expression of stress, virulence, biofilm, motility, and metabolism-related genes, many of which are controlled by these regulators, were also downregulated.…”

Section: Resultsmentioning

confidence: 99%

Quantitative mapping of mRNA 3’ ends inPseudomonas aeruginosareveals a pervasive role for premature 3’ end formation in response to azithromycin

Konikkat

Scribner

Eutsey

et al. 2020

Preprint

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P. aeruginosa produces serious chronic infections in hospitalized patients and immunocompromised individuals, including cystic fibrosis patients. The molecular mechanisms by which P. aeruginosa responds to antibiotics and other stresses to promote persistent infections may provide new avenues for therapeutic intervention. Azithromycin (AZM), an antibiotic frequently used in cystic fibrosis treatment, is thought to improve clinical outcomes through a number of mechanisms including impaired biofilm growth and QS. The mechanisms underlying the transcriptional response to AZM remain unclear. Here, we interrogated the P. aeruginosa transcriptional response to AZM using an improved genomewide approach to quantitate RNA 3'-ends (3pMap). We also identified hundreds of P.aeruginosa genes subject to premature transcription termination in their transcript leaders using 3pMap. AZM treatment of planktonic and biofilm cultures alters the expression of hundreds of genes, including those involved in QS, biofilm formation, and virulence.Strikingly, most genes downregulated by AZM in biofilms had increased levels of intragenic 3'-ends indicating premature transcription termination or pausing. Reciprocally, AZM reduced premature transcription termination in many upregulated genes. Most notably, reduced termination accompanied robust induction of obgE, a GTPase involved in persister formation in P. aeruginosa. Our results support a model in which AZM-induced premature transcription termination downregulates expression of central transcriptional regulators, which in turn both impairs QS and biofilm formation, and stress responses, while upregulating genes associated with persistence.

show abstract

The aminoglycoside resistance-promoting AmgRS envelope stress-responsive two-component system in Pseudomonas aeruginosa is zinc-activated and protects cells from zinc-promoted membrane damage

Cited by 13 publications

References 70 publications

Quantitative mapping of mRNA 3’ ends in Pseudomonas aeruginosa reveals a pervasive role for premature 3’ end formation in response to azithromycin

Quantitative mapping of mRNA 3’ ends in Pseudomonas aeruginosa reveals a pervasive role for premature 3’ end formation in response to azithromycin

Availability of Zinc Impacts Interactions between Streptococcus sanguinis and Pseudomonas aeruginosa in Coculture

Quantitative mapping of mRNA 3’ ends inPseudomonas aeruginosareveals a pervasive role for premature 3’ end formation in response to azithromycin

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