scholarly journals Probing the evolutionary robustness of two repurposed drugs targeting iron uptake in Pseudomonas aeruginosa

2018 ◽  
Author(s):  
Chiara Rezzoagli ◽  
David Wilson ◽  
Michael Weigert ◽  
Stefan Wyder ◽  
Rolf Kümmerli
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Iron Uptake ◽  
Evolutionary Robustness ◽  
Repurposed Drugs

scholarly journals Probing the evolutionary robustness of two repurposed drugs targeting iron uptake inPseudomonas aeruginosa

2017 ◽  
Author(s):  
Chiara Rezzoagli ◽  
David Wilson ◽  
Michael Weigert ◽  
Stefan Wyder ◽  
Rolf Kümmerli
Keyword(s):  
Iron Uptake ◽  
Ex Vivo ◽  
Iron Acquisition ◽  
Great Promise ◽  
Infection Model ◽  
Evolutionary Robustness ◽  
Repurposed Drugs ◽  
Opportunistic Human Pathogen ◽  
Iron Delivery ◽  
Conventional Antibiotics

AbstractBackground and objectivesTreatments that inhibit the expression or functioning of bacterial virulence factors hold great promise to be both effective and exert weaker selection for resistance than conventional antibiotics. However, the evolutionary robustness argument, based on the idea that anti-virulence treatments disarm rather than kill pathogens, is controversial. Here we probe the evolutionary robustness of two repurposed drugs, gallium and flucytosine, targeting the iron-scavenging pyoverdine of the opportunistic human pathogenPseudomonas aeruginosa.MethodologyWe subjected replicated cultures of bacteria to two concentrations of each drug for 20 consecutive days in human serum as an ex-vivo infection model. We screened evolved populations and clones for resistance phenotypes, including the restoration of growth and pyoverdine production, and the evolution of iron uptake by-passing mechanisms. We whole-genome sequenced evolved clones to identify the genetic basis of resistance.ResultsWe found that mutants resistant against anti-virulence treatments readily arose, but their selective spreading varied between treatments. Flucytosine resistance quickly spread in all populations due to disruptive mutations inupp, a gene encoding an enzyme required for flucytosine activation. Conversely, resistance against gallium arose only sporadically, and was based on mutations in transcriptional regulators, upregulating pyocyanin production, a redox-active molecule promoting siderophore-independent iron acquisition. The spread of gallium resistance could be hampered because pyocyanin-mediated iron delivery benefits resistant and susceptible cells alike.Conclusions and implicationsOur work highlights that anti-virulence treatments are not evolutionarily robustper se. Instead, evolutionary robustness is a relative measure, with specific treatments occupying different positions on a continuous scale.

scholarly journals Pyoverdine-Mediated Iron Uptake in Pseudomonas aeruginosa: the Tat System Is Required for PvdN but Not for FpvA Transport

2006 ◽  
Vol 188 (9) ◽  
pp. 3317-3323 ◽  
Author(s):  
Romé Voulhoux ◽  
Alain Filloux ◽  
Isabelle J. Schalk
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Iron Uptake ◽  
Cytoplasmic Membrane ◽  
Signal Sequence ◽  
Iron Release ◽  
Outer Membrane Receptor ◽  
Uptake Pathway ◽  
Uptake Process ◽  
Tat System

ABSTRACT Under iron-limiting conditions, Pseudomonas aeruginosa PAO1 secretes a fluorescent siderophore called pyoverdine (Pvd). After chelating iron, this ferric siderophore is transported back into the cells via the outer membrane receptor FpvA. The Pvd-dependent iron uptake pathway requires several essential genes involved in both the synthesis of Pvd and the uptake of ferric Pvd inside the cell. A previous study describing the global phenotype of a tat-deficient P. aeruginosa strain showed that the defect in Pvd-mediated iron uptake was due to the Tat-dependent export of proteins involved in Pvd biogenesis and ferric Pvd uptake (U. Ochsner, A. Snyder, A. I. Vasil, and M. L. Vasil, Proc. Natl. Acad. Sci. USA 99:8312-8317, 2002). Using biochemical and biophysical tools, we showed that despite its predicted Tat signal sequence, FpvA is correctly located in the outer membrane of a tat mutant and is fully functional for all steps of the iron uptake process (ferric Pvd uptake and recycling of Pvd on FpvA after iron release). However, in the tat mutant, no Pvd was produced. This suggested that a key element in the Pvd biogenesis pathway must be exported to the periplasm by the Tat pathway. We located PvdN, a still unknown but essential component in Pvd biogenesis, at the periplasmic side of the cytoplasmic membrane and showed that its export is Tat dependent. Our results further support the idea that a critical step of the Pvd biogenesis pathway involving PvdN occurs at the periplasmic side of the cytoplasmic membrane.

A new mechanism for membrane iron transport in Pseudomonas aeruginosa

2002 ◽  
Vol 30 (4) ◽  
pp. 702-705 ◽  
Author(s):  
I.J. Schalk ◽  
M. A. Abdallah ◽  
F. Pattus
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Iron Uptake ◽  
Iron Transport ◽  
Membrane Receptor ◽  
Gram Negative Bacteria ◽  
Outer Membrane Receptor ◽  
Uptake Mechanism ◽  
Atp Binding Cassette Transporter ◽  
Biophysical Studies

Various biochemical and biophysical studies have demonstrated the existence of a novel iron-uptake mechanism in Pseudomonas aeruginosa, different from that generally described for ferrichrome and ferric-enterobactin in Escherichia coli. This new iron-uptake mechanism involves all the proteins generally reported to be involved in the uptake of ferric-siderophore complexes in Gram-negative bacteria (i.e. the outer membrane receptor, periplasmic binding protein and ATP-binding-cassette transporter), but differs in the behaviour of the siderophore. One of the key features of this process is the binding of iron-free pyoverdin to the outer membrane receptor FpvA in conditions of iron deficiency.

scholarly journals Citrate-mediated iron uptake in Pseudomonas aeruginosa: involvement of the citrate-inducible FecA receptor and the FeoB ferrous iron transporter

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 305-315 ◽  
Author(s):  
Bryan Marshall ◽  
Alain Stintzi ◽  
Christie Gilmour ◽  
Jean-Marie Meyer ◽  
Keith Poole
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ferrous Iron ◽  
Iron Uptake ◽  
Ferric Citrate ◽  
Uptake System ◽  
Mutant Library ◽  
Fe Uptake ◽  
Subsequent Elimination ◽  
Fe Acquisition ◽  
Additional Loss

In an attempt to identify components of a ferric citrate uptake system in Pseudomonas aeruginosa, a mutant library of a siderophore-deficient strain (IA614) was constructed and screened for defects in citrate-promoted growth in an Fe-restricted medium. A mutant disrupted in gene PA3901, encoding a homologue of the outer-membrane ferric citrate receptor, FecA, of Escherichia coli (FecAE.c.), was recovered and shown to be deficient in citrate-promoted growth and citrate-mediated Fe uptake. A mutant disrupted in gene PA4825, encoding a homologue of the MgtA/MgtB Mg2+ transporters in Salmonella enterica, was similarly deficient in citrate-promoted growth, though this was due to a citrate sensitivity of the mutant apparently resulting from citrate-promoted acquisition of Fe2+ and resultant oxidative stress. Consistent with citrate delivering Fe to cells as Fe2+, a P. aeruginosa mutant lacking the FeoB Fe2+ transporter homologue, PA4358, was compromised for citrate-promoted growth in Fe-restricted medium and showed markedly reduced citrate-mediated Fe uptake. Subsequent elimination of two Fe3+ transporter homologues, PA5216 and PA4687, in the feoB mutant failed to further compromise citrate-promoted growth or Fe uptake, though the additional loss of pcoA, encoding a periplasmic ferroxidase implicated in Fe2+ acquisition, completely abrogated citrate-mediated Fe uptake. Fe acquisition mediated by other siderophores (e.g. pyoverdine) was, however, unaffected in the quadruple knockout strain. These data indicate that Fe delivered to P. aeruginosa by citrate is released as Fe2+, probably in the periplasm, prior to its transport into cells via Fe transport components.

scholarly journals How the Presence of Hemin Affects the Expression of the Different Iron Uptake Pathways in Pseudomonas aeruginosa Cells

2021 ◽  
Author(s):  
Vincent Normant ◽  
Lauriane Kuhn ◽  
Mathilde Munier ◽  
Philippe Hammann ◽  
Gaëtan L. A. Mislin ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Iron Uptake

Role of the high-affinity reductive iron acquisition pathway of Candida albicans in prostaglandin E2 production, virulence, and interaction with Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Bonang M Mochochoko ◽  
Obinna T Ezeokoli ◽  
Olihile Sebolai ◽  
Jacobus Albertyn ◽  
Carolina H Pohl
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Candida Albicans ◽  
Prostaglandin E2 ◽  
Biofilm Formation ◽  
Iron Uptake ◽  
Iron Homeostasis ◽  
Pge2 Production ◽  
Oxidase Gene ◽  
Reductive Pathway

Abstract Components of the iron reductive pathway of Candida albicans have been implicated in the production of prostaglandin E2 (PGE2) and virulence. However, it is unknown whether other components of this pathway influence PGE2. We investigated the role of the iron reductive pathway of C. albicans in biofilm formation, PGE2 production, and virulence in Caenorhabditis elegans. Additionally, as the co-occurrence of C. albicans and Pseudomonas aeruginosa in host tissues is frequent and involves competition for host-associated iron, we examined the effects of this interaction. Deletion of multicopper oxidase gene, FET99, and iron permease genes, FTH1 and FTH2, affected biofilm metabolic activity, and for the FTH2 mutant, also biofilm morphology. Deletion of CCC1 (vacuolar iron transporter) and CCC2 (P-type ATPase copper importer) also influenced biofilm morphology. For PGE2 production, deletion of FET99, FTH1, FTH2, CCC1, and CCC2 caused a significant reduction by monomicrobial biofilms, while FTH2deletion caused the highest reduction in polymicrobial biofilms. URA3 positive mutants of FET99 and FTH2 demonstrated attenuated virulence in C. elegans, potentially due to the inability of mutants to form hyphae in vivo. Deductively, the role of the iron reductive pathway in PGE2 synthesis is indirect, possibly due to their role in iron homeostasis. Lay Summary Iron uptake is vital for disease-causing microbes like Candida albicans. Using strains deficient in some iron-uptake genes, we show that iron-uptake genes, especially FET99 and FTH2, play a role in biofilm formation, prostaglandin production, and virulence in the nematode infection model.

Sign in / Sign up

Export Citation Format

Share Document