1
|
Trouillon J, Attrée I, Elsen S. The regulation of bacterial two-partner secretion systems. Mol Microbiol 2023; 120:159-177. [PMID: 37340956 DOI: 10.1111/mmi.15112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 06/01/2023] [Accepted: 06/07/2023] [Indexed: 06/22/2023]
Abstract
Two-partner secretion (TPS) systems, also known as Type Vb secretion systems, allow the translocation of effector proteins across the outer membrane of Gram-negative bacteria. By secreting different classes of effectors, including cytolysins and adhesins, TPS systems play important roles in bacterial pathogenesis and host interactions. Here, we review the current knowledge on TPS systems regulation and highlight specific and common regulatory mechanisms across TPS functional classes. We discuss in detail the specific regulatory networks identified in various bacterial species and emphasize the importance of understanding the context-dependent regulation of TPS systems. Several regulatory cues reflecting host environment during infection, such as temperature and iron availability, are common determinants of expression for TPS systems, even across relatively distant species. These common regulatory pathways often affect TPS systems across subfamilies with different effector functions, representing conserved global infection-related regulatory mechanisms.
Collapse
Affiliation(s)
- Julian Trouillon
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, Grenoble, France
| | - Ina Attrée
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, Grenoble, France
| | - Sylvie Elsen
- Université Grenoble Alpes, CNRS, CEA, IBS UMR 5075, Team Bacterial Pathogenesis and Cellular Responses, Grenoble, France
| |
Collapse
|
2
|
Sánchez-Jiménez A, Llamas MA, Marcos-Torres FJ. Transcriptional Regulators Controlling Virulence in Pseudomonas aeruginosa. Int J Mol Sci 2023; 24:11895. [PMID: 37569271 PMCID: PMC10418997 DOI: 10.3390/ijms241511895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/13/2023] Open
Abstract
Pseudomonas aeruginosa is a pathogen capable of colonizing virtually every human tissue. The host colonization competence and versatility of this pathogen are powered by a wide array of virulence factors necessary in different steps of the infection process. This includes factors involved in bacterial motility and attachment, biofilm formation, the production and secretion of extracellular invasive enzymes and exotoxins, the production of toxic secondary metabolites, and the acquisition of iron. Expression of these virulence factors during infection is tightly regulated, which allows their production only when they are needed. This process optimizes host colonization and virulence. In this work, we review the intricate network of transcriptional regulators that control the expression of virulence factors in P. aeruginosa, including one- and two-component systems and σ factors. Because inhibition of virulence holds promise as a target for new antimicrobials, blocking the regulators that trigger the production of virulence determinants in P. aeruginosa is a promising strategy to fight this clinically relevant pathogen.
Collapse
Affiliation(s)
| | - María A. Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
| | - Francisco Javier Marcos-Torres
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
| |
Collapse
|
3
|
Teng S, Wu T, Gao D, Wu S, Xiao Y, Long Y, Xie Z. Insight into the Global Negative Regulation of Iron Scavenger 7-HT Biosynthesis by the SigW/RsiW System in Pseudomonas donghuensis HYS. Int J Mol Sci 2023; 24:ijms24021184. [PMID: 36674714 PMCID: PMC9861184 DOI: 10.3390/ijms24021184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
7-Hydroxytropolone (7-HT) is a unique iron scavenger synthesized by Pseudomonas donghuensis HYS that has various biological activities in addition to functioning as a siderophore. P. donghuensis HYS is more pathogenic than P. aeruginosa toward Caenorhabditis elegans, an observation that is closely linked to the biosynthesis of 7-HT. The nonfluorescent siderophore (nfs) gene cluster is responsible for the orderly biosynthesis of 7-HT and represents a competitive advantage that contributes to the increased survival of P. donghuensis HYS; however, the regulatory mechanisms of 7-HT biosynthesis remain unclear. This study is the first to propose that the ECF σ factor has a regulatory effect on 7-HT biosynthesis. In total, 20 ECF σ factors were identified through genome-wide scanning, and their responses to extracellular ferrous ions were characterized. We found that SigW was both significantly upregulated under high-iron conditions and repressed by an adjacent anti-σ factor. RNA-Seq results suggest that the SigW/RsiW system is involved in iron metabolism and 7-HT biosynthesis. Combined with the siderophore phenotype, we also found that SigW could inhibit siderophore synthesis, and this inhibition can be relieved by RsiW. EMSA assays proved that SigW, when highly expressed, can directly bind to the promoter region of five operons of the nfs cluster to inhibit the transcription of the corresponding genes and consequently suppress 7-HT biosynthesis. In addition, SigW not only directly negatively regulates structural genes related to 7-HT synthesis but also inhibits the transcription of regulatory proteins, including of the Gac/Rsm cascade system. Taken together, our results highlight that the biosynthesis of 7-HT is negatively regulated by SigW and that the SigW/RsiW system is involved in mechanisms for the regulation of iron homeostasis in P. donghuensis HYS. As a result of this work, we identified a novel mechanism for the global negative regulation of 7-HT biosynthesis, complementing our understanding of the function of ECF σ factors in Pseudomonas.
Collapse
|
4
|
Virulence Induction in Pseudomonas aeruginosa under Inorganic Phosphate Limitation: a Proteomics Perspective. Microbiol Spectr 2022; 10:e0259022. [PMID: 36354317 PMCID: PMC9769906 DOI: 10.1128/spectrum.02590-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Inorganic phosphate (Pi) is a central nutrient and signal molecule for bacteria. Pi limitation was shown to increase the virulence of several phylogenetically diverse pathogenic bacteria with different lifestyles. Hypophosphatemia enhances the risk of death in patients due to general bacteremia and was observed after surgical injury in humans. Phosphate therapy, or the reduction of bacterial virulence by the administration of Pi or phosphate-containing compounds, is a promising anti-infective therapy approach that will not cause cytotoxicity or the emergence of antibiotic-resistant strains. The proof of concept of phosphate therapy has been obtained using primarily Pseudomonas aeruginosa (PA). However, a detailed understanding of Pi-induced changes at protein levels is missing. Using pyocyanin production as proxy, we show that the Pi-mediated induction of virulence is a highly cooperative process that occurs between 0.2 to 0.6 mM Pi. We present a proteomics study of PA grown in minimal medium supplemented with either 0.2 mM or 1 mM Pi and rich medium. About half of the predicted PA proteins could be quantified. Among the 1,471 dysregulated proteins comparing growth in 0.2 mM to 1 mM Pi, 1,100 were depleted under Pi-deficient conditions. Most of these proteins are involved in general and energy metabolism, different biosynthetic and catabolic routes, or transport. Pi depletion caused accumulation of proteins that belong to all major families of virulence factors, including pyocyanin synthesis, secretion systems, quorum sensing, chemosensory signaling, and the secretion of proteases, phospholipases, and phosphatases, which correlated with an increase in exoenzyme production and antibacterial activity. IMPORTANCE Antibiotics are our main weapons to fight pathogenic bacteria, but the increase in antibiotic-resistant strains and their consequences represents a major global health challenge, revealing the necessity to develop alternative antimicrobial strategies that do not involve the bacterial killing or growth inhibition. P. aeruginosa has been placed second on the global priority list to guide research on the development of new antibiotics. One of the most promising alternative strategies is the phosphate therapy for which the proof of concept has been obtained for P. aeruginosa. This article reports the detailed changes at the protein levels comparing P. aeruginosa grown under Pi-abundant and Pi-depleted conditions. These data describe in detail the molecular mechanisms underlying phosphate therapy. Apart from Pi, several other phosphate-containing compounds have been used for phosphate therapy and this study will serve as a reference for comparative studies aimed at evaluating the effect of alternative compounds.
Collapse
|
5
|
Adamer MF, Brüningk SC, Tejada-Arranz A, Estermann F, Basler M, Borgwardt K. reComBat: batch-effect removal in large-scale multi-source gene-expression data integration. BIOINFORMATICS ADVANCES 2022; 2:vbac071. [PMID: 36699372 PMCID: PMC9710604 DOI: 10.1093/bioadv/vbac071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/01/2022] [Accepted: 09/26/2022] [Indexed: 01/28/2023]
Abstract
Motivation With the steadily increasing abundance of omics data produced all over the world under vastly different experimental conditions residing in public databases, a crucial step in many data-driven bioinformatics applications is that of data integration. The challenge of batch-effect removal for entire databases lies in the large number of batches and biological variation, which can result in design matrix singularity. This problem can currently not be solved satisfactorily by any common batch-correction algorithm. Results We present reComBat, a regularized version of the empirical Bayes method to overcome this limitation and benchmark it against popular approaches for the harmonization of public gene-expression data (both microarray and bulkRNAsq) of the human opportunistic pathogen Pseudomonas aeruginosa. Batch-effects are successfully mitigated while biologically meaningful gene-expression variation is retained. reComBat fills the gap in batch-correction approaches applicable to large-scale, public omics databases and opens up new avenues for data-driven analysis of complex biological processes beyond the scope of a single study. Availability and implementation The code is available at https://github.com/BorgwardtLab/reComBat, all data and evaluation code can be found at https://github.com/BorgwardtLab/batchCorrectionPublicData. Supplementary information Supplementary data are available at Bioinformatics Advances online.
Collapse
Affiliation(s)
| | | | | | | | - Marek Basler
- Biozentrum, University of Basel, Basel 4056, Switzerland
| | - Karsten Borgwardt
- Department of Biosystems Science and Engineering, ETH Zurich, Basel 4058, Switzerland,Swiss Institute for Bioinformatics (SIB), Lausanne 1015, Switzerland
| |
Collapse
|
6
|
Multidrug-Resistant Biofilm, Quorum Sensing, Quorum Quenching, and Antibacterial Activities of Indole Derivatives as Potential Eradication Approaches. BIOMED RESEARCH INTERNATIONAL 2022; 2022:9048245. [PMID: 36060142 PMCID: PMC9433265 DOI: 10.1155/2022/9048245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 06/21/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022]
Abstract
Challenges encountered in relapse of illness caused by resistance of microorganisms to antimicrobial agents (drugs) are due to factors of severe stress initiated by random use of antibiotics and insufficient beneficial approaches. These challenges have resulted to multiple drug resistance (MDR) and, subsequently, biofilm formation. A type of intercellular communication signal called quorum sensing (QS) has been studied to cause the spread of resistance, thereby enabling a formation of stable community for microorganisms. The QS could be inhibited using QS inhibitors (QSIs) called quorum-quenching (QQ). The QQ is an antibiofilm agent. Indole derivatives from plant sources can serve as quorum-quenching eradication approach for biofilm, as well as a promising nontoxic antibiofilm agent. In other words, phytochemicals in plants help to control and prevent biofilm formation. It could be recommended that combination strategies of these indoles' derivatives with antibiotics would yield enhanced results.
Collapse
|
7
|
Iron Homeostasis in Pseudomonas aeruginosa: Targeting Iron Acquisition and Storage as an Antimicrobial Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:29-68. [DOI: 10.1007/978-3-031-08491-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
8
|
Specific and Global RNA Regulators in Pseudomonas aeruginosa. Int J Mol Sci 2021; 22:ijms22168632. [PMID: 34445336 PMCID: PMC8395346 DOI: 10.3390/ijms22168632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/05/2021] [Accepted: 08/08/2021] [Indexed: 01/20/2023] Open
Abstract
Pseudomonas aeruginosa (Pae) is an opportunistic pathogen showing a high intrinsic resistance to a wide variety of antibiotics. It causes nosocomial infections that are particularly detrimental to immunocompromised individuals and to patients suffering from cystic fibrosis. We provide a snapshot on regulatory RNAs of Pae that impact on metabolism, pathogenicity and antibiotic susceptibility. Different experimental approaches such as in silico predictions, co-purification with the RNA chaperone Hfq as well as high-throughput RNA sequencing identified several hundreds of regulatory RNA candidates in Pae. Notwithstanding, using in vitro and in vivo assays, the function of only a few has been revealed. Here, we focus on well-characterized small base-pairing RNAs, regulating specific target genes as well as on larger protein-binding RNAs that sequester and thereby modulate the activity of translational repressors. As the latter impact large gene networks governing metabolism, acute or chronic infections, these protein-binding RNAs in conjunction with their cognate proteins are regarded as global post-transcriptional regulators.
Collapse
|
9
|
Fan K, Cao Q, Lan L. Genome-Wide Mapping Reveals Complex Regulatory Activities of BfmR in Pseudomonas aeruginosa. Microorganisms 2021; 9:485. [PMID: 33668961 PMCID: PMC8025907 DOI: 10.3390/microorganisms9030485] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/09/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023] Open
Abstract
BfmR is a response regulator that modulates diverse pathogenic phenotypes and induces an acute-to-chronic virulence switch in Pseudomonas aeruginosa, an important human pathogen causing serious nosocomial infections. However, the mechanisms of action of BfmR remain largely unknown. Here, using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), we showed that 174 chromosomal regions of P. aeruginosa MPAO1 genome were highly enriched by coimmunoprecipitation with a C-terminal Flag-tagged BfmR. Integration of these data with global transcriptome analyses revealed that 172 genes in 106 predicted transcription units are potential targets for BfmR. We determined that BfmR binds to and modulates the promoter activity of genes encoding transcriptional regulators CzcR, ExsA, and PhoB. Intriguingly, BfmR bound to the promoters of a number of genes belong to either CzcR or PhoB regulon, or both, indicating that CzcRS and PhoBR two-component systems (TCSs) deeply feed into the BfmR-mediated regulatory network. In addition, we demonstrated that phoB is required for BfmR to promote the biofilm formation by P. aeruginosa. These results delineate the direct BfmR regulon and exemplify the complexity of BfmR-mediated regulation of cellular functions in P. aeruginosa.
Collapse
Affiliation(s)
- Ke Fan
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China;
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
| | - Qiao Cao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
| | - Lefu Lan
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China;
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China;
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
- NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology, Shanghai Institute for Food and Drug Control, Shanghai 201203, China
| |
Collapse
|
10
|
Conditional antagonism in co-cultures of Pseudomonas aeruginosa and Candida albicans: An intersection of ethanol and phosphate signaling distilled from dual-seq transcriptomics. PLoS Genet 2020; 16:e1008783. [PMID: 32813693 PMCID: PMC7480860 DOI: 10.1371/journal.pgen.1008783] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 09/09/2020] [Accepted: 06/20/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa and Candida albicans are opportunistic pathogens whose interactions involve the secreted products ethanol and phenazines. Here, we describe the role of ethanol in mixed-species co-cultures by dual-seq analyses. P. aeruginosa and C. albicans transcriptomes were assessed after growth in mono-culture or co-culture with either ethanol-producing C. albicans or a C. albicans mutant lacking the primary ethanol dehydrogenase, Adh1. Analysis of the RNA-Seq data using KEGG pathway enrichment and eADAGE methods revealed several P. aeruginosa responses to C. albicans-produced ethanol including the induction of a non-canonical low-phosphate response regulated by PhoB. C. albicans wild type, but not C. albicans adh1Δ/Δ, induces P. aeruginosa production of 5-methyl-phenazine-1-carboxylic acid (5-MPCA), which forms a red derivative within fungal cells and exhibits antifungal activity. Here, we show that C. albicans adh1Δ/Δ no longer activates P. aeruginosa PhoB and PhoB-regulated phosphatase activity, that exogenous ethanol complements this defect, and that ethanol is sufficient to activate PhoB in single-species P. aeruginosa cultures at permissive phosphate levels. The intersection of ethanol and phosphate in co-culture is inversely reflected in C. albicans; C. albicans adh1Δ/Δ had increased expression of genes regulated by Pho4, the C. albicans transcription factor that responds to low phosphate, and Pho4-dependent phosphatase activity. Together, these results show that C. albicans-produced ethanol stimulates P. aeruginosa PhoB activity and 5-MPCA-mediated antagonism, and that both responses are dependent on local phosphate concentrations. Further, our data suggest that phosphate scavenging by one species improves phosphate access for the other, thus highlighting the complex dynamics at play in microbial communities. Pseudomonas aeruginosa and Candida albicans are opportunistic pathogens that are frequently isolated from co-infections. Using a combination of dual-seq transcriptomics and genetics approaches, we found that ethanol produced by C. albicans stimulates the PhoB regulon in P. aeruginosa asynchronously with activation of the Pho4 regulon in C. albicans. We validated our result by showing that PhoB plays multiple roles in co-culture including orchestrating the competition for phosphate and the production of 5-methyl-phenazine-1-carboxylic acid; the P. aeruginosa phenazine response to C. albicans-produced ethanol depends on phosphate availability. The conditional stimulation of antifungal production in response to sub-inhibitory concentrations of ethanol only under phosphate limitation highlights the importance of considering nutrient concentrations in the analysis of co-culture interactions and suggests that the low-phosphate response in one species influences phosphate availability for the other.
Collapse
|
11
|
Otero-Asman JR, Quesada JM, Jim KK, Ocampo-Sosa A, Civantos C, Bitter W, Llamas MA. The extracytoplasmic function sigma factor σ VreI is active during infection and contributes to phosphate starvation-induced virulence of Pseudomonas aeruginosa. Sci Rep 2020; 10:3139. [PMID: 32081993 PMCID: PMC7035377 DOI: 10.1038/s41598-020-60197-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 02/07/2020] [Indexed: 12/27/2022] Open
Abstract
The extracytoplasmic function sigma factor σVreI of the human pathogen Pseudomonas aeruginosa promotes transcription of potential virulence determinants, including secretion systems and secreted proteins. Its activity is modulated by the VreR anti-σ factor that inhibits the binding of σVreI to the RNA polymerase in the absence of a (still unknown) inducing signal. The vreI-vreR genes are expressed under inorganic phosphate (Pi) starvation, a physiological condition often encountered in the host that increases P. aeruginosa pathogenicity. However, whether or not σVreI is active in vivo during infection and contributes to the Pi starvation-induced virulence of this pathogen has not been analyzed yet. Using zebrafish embryos and a human alveolar basal epithelial cell line as P. aeruginosa hosts, we demonstrate in this work that σVreI is active during infection and that lack of σVreI considerably reduces the Pi starvation-induced virulence of this pathogen. Surprisingly, lack of the σVreI inhibitor, the VreR anti-σ factor, also diminishes the virulence of P. aeruginosa. By transcriptomic analyses we show that VreR modulates gene expression not only in a σVreI-dependent but also in a σVreI-independent manner. This includes potential virulence determinants and transcriptional regulators that could be responsible for the reduced virulence of the ΔvreR mutant.
Collapse
Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - José M Quesada
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Kin K Jim
- Department of Medical Microbiology and Infection Control, Amsterdam University medical centers, location VU University, Amsterdam, The Netherlands
| | - Alain Ocampo-Sosa
- Service of Microbiology, Hospital Universitario Marqués de Valdecilla-Instituto de Investigación Sanitaria Valdecilla, Santander, Spain
| | - Cristina Civantos
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, Amsterdam University medical centers, location VU University, Amsterdam, The Netherlands
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain.
| |
Collapse
|
12
|
Otero-Asman JR, García-García AI, Civantos C, Quesada JM, Llamas MA. Pseudomonas aeruginosa possesses three distinct systems for sensing and using the host molecule haem. Environ Microbiol 2019; 21:4629-4647. [PMID: 31390127 DOI: 10.1111/1462-2920.14773] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022]
Abstract
Pathogens have developed several strategies to obtain iron during infection, including the use of iron-containing molecules from the host. Haem accounts for the vast majority of the iron pool in vertebrates and thus represents an important source of iron for pathogens. Using a proteomic approach, we have identified in this work a previously uncharacterized system, which we name Hxu, that together with the known Has and Phu systems, is used by the human pathogen Pseudomonas aeruginosa to respond to haem. We show that the Has and Hxu systems are functional signal transduction pathways of the cell-surface signalling class and report the mechanism triggering the activation of these signalling systems. Both signalling cascades involve an outer membrane receptor (HasR and HxuA respectively) that upon sensing haem in the extracellular medium produces the activation of an σECF factor in the cytosol. HxuA has a major role in signalling and a minor role in haem acquisition in conditions in which the HasR and PhuR receptors or other sources of iron are present. Remarkably, P. aeruginosa compensates the lack of the HasR receptor by increasing the production of HxuA, which underscores the importance of haem signalling for this pathogen.
Collapse
Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - Ana I García-García
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - Cristina Civantos
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - José M Quesada
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| |
Collapse
|
13
|
Otero-Asman JR, Wettstadt S, Bernal P, Llamas MA. Diversity of extracytoplasmic function sigma (σ ECF ) factor-dependent signaling in Pseudomonas. Mol Microbiol 2019; 112:356-373. [PMID: 31206859 DOI: 10.1111/mmi.14331] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2019] [Indexed: 12/23/2022]
Abstract
Pseudomonas bacteria are widespread and are found in soil and water, as well as pathogens of both plants and animals. The ability of Pseudomonas to colonize many different environments is facilitated by the multiple signaling systems these bacteria contain that allow Pseudomonas to adapt to changing circumstances by generating specific responses. Among others, signaling through extracytoplasmic function σ (σECF ) factors is extensively present in Pseudomonas. σECF factors trigger expression of functions required under particular conditions in response to specific signals. This manuscript reviews the phylogeny and biological roles of σECF factors in Pseudomonas, and highlights the diversity of σECF -signaling pathways of this genus in terms of function and activation. We show that Pseudomonas σECF factors belong to 16 different phylogenetic groups. Most of them are included within the iron starvation group and are mainly involved in iron acquisition. The second most abundant group is formed by RpoE-like σECF factors, which regulate the responses to cell envelope stress. Other groups controlling solvent tolerance, biofilm formation and the response to oxidative stress, among other functions, are present in lower frequency. The role of σECF factors in the virulence of Pseudomonas pathogenic species is described.
Collapse
Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Sarah Wettstadt
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Patricia Bernal
- Department of Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| |
Collapse
|
14
|
Chevalier S, Bouffartigues E, Bazire A, Tahrioui A, Duchesne R, Tortuel D, Maillot O, Clamens T, Orange N, Feuilloley MGJ, Lesouhaitier O, Dufour A, Cornelis P. Extracytoplasmic function sigma factors in Pseudomonas aeruginosa. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:706-721. [PMID: 29729420 DOI: 10.1016/j.bbagrm.2018.04.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/06/2018] [Accepted: 04/30/2018] [Indexed: 01/26/2023]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa, like all members of the genus Pseudomonas, has the capacity to thrive in very different environments, ranging from water, plant roots, to animals, including humans to whom it can cause severe infections. This remarkable adaptability is reflected in the number of transcriptional regulators, including sigma factors in this bacterium. Among those, the 19 to 21 extracytoplasmic sigma factors (ECFσ) are endowed with different regulons and functions, including the iron starvation σ (PvdS, FpvI, HasI, FecI, FecI2 and others), the cell wall stress ECFσ AlgU, SigX and SbrI, and the unorthodox σVreI involved in the expression of virulence. Recently published data show that these ECFσ have separate regulons although presenting some cross-talk. We will present evidence that these different ECFσ are involved in the expression of different phenotypes, ranging from cell-wall stress response, production of extracellular polysaccharides, formation of biofilms, to iron acquisition.
Collapse
Affiliation(s)
- Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France.
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alexis Bazire
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Rachel Duchesne
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Damien Tortuel
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Maillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Thomas Clamens
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Nicole Orange
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alain Dufour
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Pierre Cornelis
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| |
Collapse
|
15
|
Liu Y, Wang Z, Bilal M, Hu H, Wang W, Huang X, Peng H, Zhang X. Enhanced Fluorescent Siderophore Biosynthesis and Loss of Phenazine-1-Carboxamide in Phenotypic Variant of Pseudomonas chlororaphis HT66. Front Microbiol 2018; 9:759. [PMID: 29740409 PMCID: PMC5924801 DOI: 10.3389/fmicb.2018.00759] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 04/04/2018] [Indexed: 11/17/2022] Open
Abstract
Pseudomonas chlororaphis HT66 is a plant-beneficial bacterium that exhibits wider antagonistic spectrum against a variety of plant pathogenic fungi due to its main secondary metabolite, i.e., phenazine-1-carboxamide (PCN). In the present study, a spontaneous phenotypic variant designated as HT66-FLUO was isolated from the fermentation process of wild-type HT66 strain. The newly isolated phenotypic variant was morphologically distinct from the wild-type strain such as larger cell size, semi-transparent, non-production of PCN (Green or yellow crystals) and enhanced fluorescence under UV light. The whole-genome, RNA-sequencing, and phenotypic assays were performed to identify the reason of phenotypic variation in HT66-FLUO as compared to the HT66. Transcriptomic analysis revealed that 1,418 genes, representing approximately 22% of the 6393 open reading frames (ORFs) had undergone substantial reprogramming of gene expression in the HT66-FLUO. The whole-genome sequence indicated no gene alteration in HT66-FLUO as compared to HT66 according to the known reference sequence. The levels of global regulatory factor gacA and gacS expression were not significantly different between HT66 and HT66-FLUO. It was observed that overexpressing gacS rather than gacA in HT66-FLUO can recover switching of the variant to HT66. The β-galactosidase (LacZ) activity and qRT-PCR results indicate the downregulated expression of rsmX, rsmY, and rsmZ in HT66-FLUO as compared to HT66. Overexpressing three small RNAs in HT66-FLUO can revert switching of colony phenotype toward wild-type HT66 up to a certain degree, restore partial PCN production and reduces the fluorescent siderophores yield. However, the origin of the spontaneous phenotypic variant was difficult to be determined. In conclusion, this study helps to understand the gene regulatory effect in the spontaneous phenotypic variant.
Collapse
Affiliation(s)
- Yang Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Zheng Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Muhammad Bilal
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hongbo Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,National Experimental Teaching Center for Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xianqing Huang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Huasong Peng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
16
|
Draft Genome Sequence of Pseudomonas aeruginosa ATCC 9027, Originally Isolated from an Outer Ear Infection. GENOME ANNOUNCEMENTS 2017; 5:5/48/e01397-17. [PMID: 29192089 PMCID: PMC5722075 DOI: 10.1128/genomea.01397-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Pseudomonas aeruginosa ATCC 9027 was isolated in 1943 from a case of otitis externa and is commonly employed as a quality control strain for sterility, assessment of antibiofilm agents, and in vitro study of wound infection. Here, we present the 6.34-Mb draft genome sequence and highlight some pertinent genes that are associated with virulence.
Collapse
|
17
|
Sakurai T, Hashikura N, Minami J, Yamada A, Odamaki T, Xiao JZ. Tolerance mechanisms of human-residential bifidobacteria against lysozyme. Anaerobe 2017; 47:104-110. [PMID: 28478277 DOI: 10.1016/j.anaerobe.2017.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 04/24/2017] [Accepted: 05/01/2017] [Indexed: 12/31/2022]
Abstract
We previously reported that lysozyme present in breast milk is a selection factor for bifidobacterial colonization in infant human intestines. This study is aimed at examining their underlying mechanisms. Human-residential bifidobacteria (HRB) generally exhibited higher tolerance than non-HRB to lysozymes, except B. bifidum subspecies. To assess the involvement of enzymatic activity of lysozyme, peptidoglycan (PG) was isolated and the degree of O-acetylation (O-Ac) in 19 strains, including both HRB and non-HRB, was determined. Variety in the degree of O-Ac was observed among each of the Bifidobacterium species; however, all purified PGs were found to be tolerant to lysozyme, independent of their O-Ac degree. In addition, De-O-Ac of PGs affected the sensitivity to lysozyme of only B. longum-derived PG. To examine the non-enzymatic antibacterial activity of lysozyme on bifidobacteria, lysozyme was heat-denatured. The HRB and non-HRB strains exhibited similar patterns of susceptibility to intact lysozyme as they did to heat-denatured lysozyme. In addition, strains of B. bifidum (30 strains), which showed various tolerance of lysozyme, also exhibited similar patterns of susceptibility to intact lysozyme as they did to heat-denatured lysozyme. These results suggest that bifidobacteria are resistant to the peptidoglycan-degrading property of lysozyme, and the tolerance to lysozyme among some HRB strains is due to resistance to the non-enzymatic antibacterial activity of lysozyme.
Collapse
Affiliation(s)
- Takuma Sakurai
- Morinaga Milk Industry Co., LTD, Next Generation Science Institute, 1-83, 5-Chome, Higashihara, Zama-City, Kanagawa-Pref. 252-8583, Japan
| | - Nanami Hashikura
- Morinaga Milk Industry Co., LTD, Next Generation Science Institute, 1-83, 5-Chome, Higashihara, Zama-City, Kanagawa-Pref. 252-8583, Japan
| | - Junichi Minami
- Morinaga Milk Industry Co., LTD, Food Ingredients & Technology Institute, 1-83, 5-Chome, Higashihara, Zama-City, Kanagawa-Pref. 252-8583, Japan
| | - Akio Yamada
- Morinaga Milk Industry Co., LTD, Food Ingredients & Technology Institute, 1-83, 5-Chome, Higashihara, Zama-City, Kanagawa-Pref. 252-8583, Japan
| | - Toshitaka Odamaki
- Morinaga Milk Industry Co., LTD, Next Generation Science Institute, 1-83, 5-Chome, Higashihara, Zama-City, Kanagawa-Pref. 252-8583, Japan
| | - Jin-Zhong Xiao
- Morinaga Milk Industry Co., LTD, Next Generation Science Institute, 1-83, 5-Chome, Higashihara, Zama-City, Kanagawa-Pref. 252-8583, Japan.
| |
Collapse
|