scholarly journals Disruption of Glycolysis by Nutritional Immunity Activates a Two-Component System That Coordinates a Metabolic and Antihost Response by Staphylococcus aureus

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Paola K. Párraga Solórzano ◽  
Jiangwei Yao ◽  
Charles O. Rock ◽  
Thomas E. Kehl-Fie
Keyword(s):  
Staphylococcus Aureus ◽  
Metabolic Flux ◽  
Bacterial Species ◽  
Critical Role ◽  
Dependent Manner ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Nutritional Immunity ◽  
Two Component

ABSTRACT During infection, bacteria use two-component signal transduction systems to sense and adapt to the dynamic host environment. Despite critically contributing to infection, the activating signals of most of these regulators remain unknown. This also applies to the Staphylococcus aureus ArlRS two-component system, which contributes to virulence by coordinating the production of toxins, adhesins, and a metabolic response that enables the bacterium to overcome host-imposed manganese starvation. Restricting the availability of essential transition metals, a strategy known as nutritional immunity, constitutes a critical defense against infection. In this work, expression analysis revealed that manganese starvation imposed by the immune effector calprotectin or by the absence of glycolytic substrates activates ArlRS. Manganese starvation imposed by calprotectin also activated the ArlRS system even when glycolytic substrates were present. A combination of metabolomics, mutational analysis, and metabolic feeding experiments revealed that ArlRS is activated by alterations in metabolic flux occurring in the latter half of the glycolytic pathway. Moreover, calprotectin was found to induce expression of staphylococcal leukocidins in an ArlRS-dependent manner. These studies indicated that ArlRS is a metabolic sensor that allows S. aureus to integrate multiple environmental stresses that alter glycolytic flux to coordinate an antihost response and to adapt to manganese starvation. They also established that the latter half of glycolysis represents a checkpoint to monitor metabolic state in S. aureus. Altogether, these findings contribute to understanding how invading pathogens, such as S. aureus, adapt to the host during infection and suggest the existence of similar mechanisms in other bacterial species. IMPORTANCE Two-component regulatory systems enable bacteria to adapt to changes in their environment during infection by altering gene expression and coordinating antihost responses. Despite the critical role of two-component systems in bacterial survival and pathogenesis, the activating signals for most of these regulators remain unidentified. This is exemplified by ArlRS, a Staphylococcus aureus global regulator that contributes to virulence and to resisting host-mediated restriction of essential nutrients, such as manganese. In this report, we demonstrate that manganese starvation and the absence of glycolytic substrates activate ArlRS. Further investigations revealed that ArlRS is activated when the latter half of glycolysis is disrupted, suggesting that S. aureus monitors flux through the second half of this pathway. Host-imposed manganese starvation also induced the expression of pore-forming toxins in an ArlRS-dependent manner. Cumulatively, this work reveals that ArlRS acts as a sensor that links nutritional status, cellular metabolism, and virulence regulation.

scholarly journals Staphylococcus aureus Nuclease Is an SaeRS-Dependent Virulence Factor

2013 ◽  
Vol 81 (4) ◽  
pp. 1316-1324 ◽  
Author(s):  
Michael E. Olson ◽  
Tyler K. Nygaard ◽  
Laynez Ackermann ◽  
Robert L. Watkins ◽  
Oliwia W. Zurek ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factor ◽  
Dependent Manner ◽  
Binding Studies ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Activity Measurements ◽  
Two Component

ABSTRACTSeveral prominent bacterial pathogens secrete nuclease (Nuc) enzymes that have an important role in combating the host immune response. Early studies ofStaphylococcus aureusNuc attributed its regulation to theagrquorum-sensing system. However, recent microarray data have indicated thatnucis under the control of the SaeRS two-component system, which is a major regulator ofS. aureusvirulence determinants. Here we report that thenucgene is directly controlled by the SaeRS two-component system through reporter fusion, immunoblotting, Nuc activity measurements, promoter mapping, and binding studies, and additionally, we were unable identify a notable regulatory link to theagrsystem. The observed SaeRS-dependent regulation was conserved across a wide spectrum of representativeS. aureusisolates. Moreover, with community-associated methicillin-resistantS. aureus(CA MRSA) in a mouse model of peritonitis, we observedin vivoexpression of Nuc activity in an SaeRS-dependent manner and determined that Nuc is a virulence factor that is important forin vivosurvival, confirming the enzyme's role as a contributor to invasive disease. Finally, natural polymorphisms were identified in the SaeRS proteins, one of which was linked to Nuc regulation in a CA MRSA USA300 endocarditis isolate. Altogether, our findings demonstrate that Nuc is an importantS. aureusvirulence factor and part of the SaeRS regulon.

scholarly journals Disruption of Phosphate Homeostasis Sensitizes Staphylococcus aureus to Nutritional Immunity

2020 ◽  
Vol 88 (6) ◽  
Author(s):  
Jessica L. Kelliher ◽  
Erin B. Brazel ◽  
Jana N. Radin ◽  
Eliot S. Joya ◽  
Paola K. Párraga Solórzano ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Defined Medium ◽  
Wild Type ◽  
Two Component System ◽  
Phosphate Homeostasis ◽  
Component System ◽  
Content Type ◽  
Nutritional Immunity ◽  
Two Component ◽  
Overexpressing Strain

ABSTRACT To control infection, mammals actively withhold essential nutrients, including the transition metal manganese, by a process termed nutritional immunity. A critical component of this host response is the manganese-chelating protein calprotectin. While many bacterial mechanisms for overcoming nutritional immunity have been identified, the intersection between metal starvation and other essential inorganic nutrients has not been investigated. Here, we report that overexpression of an operon encoding a highly conserved inorganic phosphate importer, PstSCAB, increases the sensitivity of Staphylococcus aureus to calprotectin-mediated manganese sequestration. Further analysis revealed that overexpression of pstSCAB does not disrupt manganese acquisition or result in overaccumulation of phosphate by S. aureus. However, it does reduce the ability of S. aureus to grow in phosphate-replete defined medium. Overexpression of pstSCAB does not aberrantly activate the phosphate-responsive two-component system PhoPR, nor was this two-component system required for sensitivity to manganese starvation. In a mouse model of systemic staphylococcal disease, a pstSCAB-overexpressing strain is significantly attenuated compared to wild-type S. aureus. This defect is partially reversed in a calprotectin-deficient mouse, in which manganese is more readily available. Given that expression of pstSCAB is regulated by PhoPR, these findings suggest that overactivation of PhoPR would diminish the ability of S. aureus to resist nutritional immunity and cause infection. As PhoPR is also necessary for bacterial virulence, these findings imply that phosphate homeostasis represents a critical regulatory node whose activity must be precisely controlled in order for S. aureus and other pathogens to cause infection.

scholarly journals The Staphylococcus aureus KdpDE Two-Component System Couples Extracellular K+Sensing and Agr Signaling to Infection Programming

2011 ◽  
Vol 79 (6) ◽  
pp. 2154-2167 ◽  
Author(s):  
Ting Xue ◽  
Yibo You ◽  
De Hong ◽  
Haipeng Sun ◽  
Baolin Sun
Keyword(s):  
Staphylococcus Aureus ◽  
Uptake System ◽  
Main Function ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Virulence Regulator ◽  
External K

ABSTRACTThe Kdp system is widely distributed among bacteria. InEscherichia coli, the Kdp-ATPase is a high-affinity K+uptake system and its expression is activated by the KdpDE two-component system in response to K+limitation or salt stress. However, information about the role of this system in many bacteria still remains obscure. Here we demonstrate that KdpFABC inStaphylococcus aureusis not a major K+transporter and that the main function of KdpDE is not associated with K+transport but that instead it regulates transcription for a series of virulence factors through sensing external K+concentrations, indicating that this bacterium might modulate its infectious status through sensing specific external K+stimuli in different environments. Our results further reveal thatS. aureusKdpDE is upregulated by the Agr/RNAIII system, which suggests that KdpDE may be an important virulence regulator coordinating the external K+sensing and Agr signaling during pathogenesis in this bacterium.

scholarly journals PhoU Allows Rapid Adaptation to High Phosphate Concentrations by Modulating PstSCAB Transport Rate in Sinorhizobium meliloti

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
George C. diCenzo ◽  
Harsh Sharthiya ◽  
Anish Nanda ◽  
Maryam Zamani ◽  
Turlough M. Finan
Keyword(s):  
Sinorhizobium Meliloti ◽  
Bacterial Species ◽  
Transport Rate ◽  
Phosphate Limitation ◽  
Rapid Adaptation ◽  
Two Component System ◽  
Phosphate Homeostasis ◽  
Component System ◽  
Content Type ◽  
Two Component

ABSTRACT Maintenance of cellular phosphate homeostasis is essential for cellular life. The PhoU protein has emerged as a key regulator of this process in bacteria, and it is suggested to modulate phosphate import by PstSCAB and control activation of the phosphate limitation response by the PhoR-PhoB two-component system. However, a proper understanding of PhoU has remained elusive due to numerous complications of mutating phoU, including loss of viability and the genetic instability of the mutants. Here, we developed two sets of strains of Sinorhizobium meliloti that overcame these limitations and allowed a more detailed and comprehensive analysis of the biological and molecular activities of PhoU. The data showed that phoU cannot be deleted in the presence of phosphate unless PstSCAB is inactivated also. However, phoU deletions were readily recovered in phosphate-free media, and characterization of these mutants revealed that addition of phosphate to the environment resulted in toxic levels of PstSCAB-mediated phosphate accumulation. Phosphate uptake experiments indicated that PhoU significantly decreased the PstSCAB transport rate specifically in phosphate-replete cells but not in phosphate-starved cells and that PhoU could rapidly respond to elevated environmental phosphate concentrations and decrease the PstSCAB transport rate. Site-directed mutagenesis results suggested that the ability of PhoU to respond to phosphate levels was independent of the conformation of the PstSCAB transporter. Additionally, PhoU-PhoU and PhoU-PhoR interactions were detected using a bacterial two-hybrid screen. We propose that PhoU modulates PstSCAB and PhoR-PhoB in response to local, internal fluctuations in phosphate concentrations resulting from PstSCAB-mediated phosphate import. IMPORTANCE Correct maintenance of cellular phosphate homeostasis is critical in all kingdoms of life and in bacteria involves the PhoU protein. This work provides novel insights into the role of the Sinorhizobium meliloti PhoU protein, which plays a key role in rapid adaptation to elevated phosphate concentrations. It is shown that PhoU rapidly responds to elevated phosphate levels by significantly decreasing the phosphate transport of PstSCAB, thereby preventing phosphate toxicity and cell death. Additionally, a new model for phosphate sensing in bacterial species which involves the PhoR-PhoB two-component system is presented. This work provides new insights into the bacterial response to changing environmental conditions and into regulation of the phosphate limitation response that influences numerous bacterial processes, including antibiotic production and virulence.

How the PhoP/PhoQ System Controls Virulence and Mg 2+ Homeostasis: Lessons in Signal Transduction, Pathogenesis, Physiology, and Evolution

2021 ◽  
Author(s):  
Eduardo A. Groisman ◽  
Alexandre Duprey ◽  
Jeongjoon Choi
Keyword(s):  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Transcriptional Regulator ◽  
Acidic Ph ◽  
Two Component System ◽  
Component System ◽  
Gram Negative ◽  
Content Type ◽  
Two Component ◽  
Serovar Typhimurium

The PhoP/PhoQ two-component system governs virulence, Mg 2+ homeostasis, and resistance to a variety of antimicrobial agents, including acidic pH and cationic antimicrobial peptides, in several Gram-negative bacterial species. Best understood in Salmonella enterica serovar Typhimurium, the PhoP/PhoQ system consists of the sensor PhoQ and the transcriptional regulator PhoP.

scholarly journals VfrB Is a Key Activator of the Staphylococcus aureus SaeRS Two-Component System

2016 ◽  
Vol 199 (5) ◽  
Author(s):  
Christina N. Krute ◽  
Kelly C. Rice ◽  
Jeffrey L. Bose
Keyword(s):  
Staphylococcus Aureus ◽  
Fatty Acid ◽  
Virulence Factors ◽  
Virulence Factor ◽  
Class I ◽  
Exponential Growth Phase ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component

ABSTRACT In previous studies, we identified the fatty acid kinase virulence factor regulator B (VfrB) as a potent regulator of α-hemolysin and other virulence factors in Staphylococcus aureus. In this study, we demonstrated that VfrB is a positive activator of the SaeRS two-component regulatory system. Analysis of vfrB, saeR, and saeS mutant strains revealed that VfrB functions in the same pathway as SaeRS. At the transcriptional level, the promoter activities of SaeRS class I (coa) and class II (hla) target genes were downregulated during the exponential growth phase in the vfrB mutant, compared to the wild-type strain. In addition, saePQRS expression was decreased in the vfrB mutant strain, demonstrating a need for this protein in the autoregulation of SaeRS. The requirement for VfrB-mediated activation was circumvented when SaeS was constitutively active due to an SaeS (L18P) substitution. Furthermore, activation of SaeS via human neutrophil peptide 1 (HNP-1) overcame the dependence on VfrB for transcription from class I Sae promoters. Consistent with the role of VfrB in fatty acid metabolism, hla expression was decreased in the vfrB mutant with the addition of exogenous myristic acid. Lastly, we determined that aspartic acid residues D38 and D40, which are predicted to be key to VfrB enzymatic activity, were required for VfrB-mediated α-hemolysin production. Collectively, this study implicates VfrB as a novel accessory protein needed for the activation of SaeRS in S. aureus. IMPORTANCE The SaeRS two-component system is a key regulator of virulence determinant production in Staphylococcus aureus. Although the regulon of this two-component system is well characterized, the activation mechanisms, including the specific signaling molecules, remain elusive. Elucidating the complex regulatory circuit of SaeRS regulation is important for understanding how the system contributes to disease causation by this pathogen. To this end, we have identified the fatty acid kinase VfrB as a positive regulatory modulator of SaeRS-mediated transcription of virulence factors in S. aureus. In addition to describing a new regulatory aspect of SaeRS, this study establishes a link between fatty acid kinase activity and virulence factor regulation.

scholarly journals Prevention of Surface-Associated Calcium Phosphate by thePseudomonas syringaeTwo-Component System CvsSR

2019 ◽  
Vol 201 (7) ◽  
Author(s):  
Maxwell R. Fishman ◽  
Melanie J. Filiatrault
Keyword(s):  
Calcium Phosphate ◽  
Carbonic Anhydrase ◽  
Pseudomonas Syringae ◽  
Dependent Manner ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Calcium Phosphate Precipitation ◽  
Calcium Precipitation

ABSTRACTCvsSR is a Ca2+-induced two-component system (TCS) in the plant pathogenPseudomonas syringaepv. tomato DC3000. Here, we discovered that CvsSR is induced by Fe3+, Zn2+, and Cd2+. However, only supplementation of Ca2+to medium resulted in rugose, opaque colonies in ΔcvsSand ΔcvsRstrains. This phenotype corresponded to formation of calcium phosphate precipitation on the surface of ΔcvsSand ΔcvsRcolonies. CvsSR regulated swarming motility inP. syringaepv. tomato in a Ca2+-dependent manner, but swarming behavior was not influenced by Fe3+, Zn2+, or Cd2+. We hypothesized that reduced swarming displayed by ΔcvsSand ΔcvsRstrains was due to precipitation of calcium phosphate on the surface of ΔcvsSand ΔcvsRcells grown on agar medium supplemented with Ca2+. By reducing the initial pH or adding glucose to the medium, calcium precipitation was inhibited, and swarming was restored to ΔcvsSand ΔcvsRstrains, suggesting that calcium precipitation influences swarming ability. Constitutive expression of a CvsSR-regulated carbonic anhydrase and a CvsSR-regulated putative sulfate major facilitator superfamily transporter in ΔcvsSand ΔcvsRstrains inhibited formation of calcium precipitates and restored the ability of ΔcvsSand ΔcvsRbacteria to swarm. Lastly, we found that glucose inhibited Ca2+-based induction of CvsSR. Hence, CvsSR is a key regulator that controls calcium precipitation on the surface of bacterial cells.IMPORTANCEBacteria are capable of precipitating and dissolving minerals. We previously reported the characterization of the two-component system CvsSR in the plant-pathogenic bacteriumPseudomonas syringae. CvsSR responds to the presence of calcium and is important for causing disease. Here, we show that CvsSR controls the ability of the bacterium to prevent calcium phosphate precipitation on the surface of cells. We also identified a carbonic anhydrase and transporter that modulate formation of surface-associated calcium precipitates. Furthermore, our results demonstrate that the ability of the bacterium to swarm is controlled by the formation and dissolution of calcium precipitates on the surface of cells. Our study describes new mechanisms for microbially induced mineralization and provides insights into the role of mineral deposits on bacterial physiology. The discoveries may lead to new technological and environmental applications.

scholarly journals Manipulation of the Anoxic Metabolism in Escherichia coli by ArcB Deletion Variants in the ArcBA Two-Component System

2012 ◽  
Vol 78 (24) ◽  
pp. 8784-8794 ◽  
Author(s):  
Gonzalo N. Bidart ◽  
Jimena A. Ruiz ◽  
Alejandra de Almeida ◽  
Beatriz S. Méndez ◽  
Pablo I. Nikel
Keyword(s):  
Escherichia Coli ◽  
Metabolic Flux ◽  
Expression Patterns ◽  
Phenotypic Traits ◽  
Wild Type ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Anoxic Conditions ◽  
Two Component

ABSTRACTBioprocesses conducted under conditions with restricted O2supply are increasingly exploited for the synthesis of reduced biochemicals using different biocatalysts. The model facultative anaerobeEscherichia colihas elaborate sensing and signal transduction mechanisms for redox control in response to the availability of O2and other electron acceptors. The ArcBA two-component system consists of ArcB, a membrane-associated sensor kinase, and ArcA, the cognate response regulator. The tripartite hybrid kinase ArcB possesses a transmembrane, a PAS, a primary transmitter (H1), a receiver (D1), and a phosphotransfer (H2) domain. Metabolic fluxes were compared under anoxic conditions in a wild-typeE. colistrain, its ΔarcBderivative, and two partialarcBdeletion mutants in which ArcB lacked either the H1 domain or the PAS-H1-D1 domains. These analyses revealed that elimination of different segments in ArcB determines a distinctive distribution ofd-glucose catabolic fluxes, different from that observed in the ΔarcBbackground. Metabolite profiles, enzyme activity levels, and gene expression patterns were also investigated in these strains. Relevant alterations were observed at the P-enol-pyruvate/pyruvate and acetyl coenzyme A metabolic nodes, and the formation of reduced fermentation metabolites, such as succinate,d-lactate, and ethanol, was favored in the mutant strains to different extents compared to the wild-type strain. These phenotypic traits were associated with altered levels of the enzymatic activities operating at these nodes, as well as with elevated NADH/NAD+ratios. Thus, targeted modification of global regulators to obtain different metabolic flux distributions under anoxic conditions is emerging as an attractive tool for metabolic engineering purposes.

scholarly journals The Two-Component System CprRS Senses Cationic Peptides and Triggers Adaptive Resistance in Pseudomonas aeruginosa Independently of ParRS

2012 ◽  
Vol 56 (12) ◽  
pp. 6212-6222 ◽  
Author(s):  
Lucía Fernández ◽  
Håvard Jenssen ◽  
Manjeet Bains ◽  
Irith Wiegand ◽  
W. James Gooderham ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Peptides ◽  
Outer Membrane ◽  
Dependent Manner ◽  
Two Component System ◽  
Concentration Dependent Manner ◽  
Component System ◽  
Content Type ◽  
Wide Range ◽  
Two Component

ABSTRACTCationic antimicrobial peptides pass across the outer membrane by interacting with negatively charged lipopolysaccharide (LPS), leading to outer membrane permeabilization in a process termed self-promoted uptake. Resistance can be mediated by the addition of positively charged arabinosamine through the action of thearnBCADTEFoperon. We recently described a series of two-component regulators that lead to the activation of thearnoperon after recognizing environmental signals, including low-Mg2+(PhoPQ, PmrAB) or cationic (ParRS) peptides. However, some peptides did not activate thearnoperon through ParRS. Here, we report the identification of a new two-component system, CprRS, which, upon exposure to a wide range of antimicrobial peptides, triggered the expression of the LPS modification operon. Thus, mutations in thecprRSoperon blocked the induction of thearnoperon in response to several antimicrobial peptides independently of ParRS but did not affect the response to low Mg2+. Distinct patterns ofarninduction were identified. Thus, the responses to polymyxins were abrogated by eitherparRorcprRmutations, while responses to other peptides, including indolicidin, showed differential dependency on the CprRS and ParRS systems in a concentration-dependent manner. It was further demonstrated that, following exposure to inducing antimicrobial peptides,cprRSmutants did not become adaptively resistant to polymyxins as was observed for wild-type cells. Our microarray studies demonstrated that the CprRS system controlled a quite modest regulon, indicating that it was quite specific to adaptive peptide resistance. These findings provide greater insight into the complex regulation of LPS modification inPseudomonas aeruginosa, which involves the participation of at least 4 two-component systems.

scholarly journals The Staphylococcus aureus SrrAB Two-Component System Promotes Resistance to Nitrosative Stress and Hypoxia

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Traci L. Kinkel ◽  
Christelle M. Roux ◽  
Paul M. Dunman ◽  
Ferric C. Fang
Keyword(s):  
Nitric Oxide ◽  
Staphylococcus Aureus ◽  
Nitrosative Stress ◽  
Electron Flow ◽  
Two Component System ◽  
Fenton Chemistry ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Sense And Respond

ABSTRACT  Staphylococcus aureusis both a commensal and a pathogen of the human host. Survival in the host environment requires resistance to host-derived nitric oxide (NO·). However,S. aureuslacks the NO·-sensing transcriptional regulator NsrR that is used by many bacteria to sense and respond to NO·. In this study, we show thatS. aureusis able to sense and respond to both NO· and hypoxia by means of the SrrAB two-component system (TCS). Analysis of theS. aureustranscriptome during nitrosative stress demonstrates the expression of SrrAB-dependent genes required for cytochrome biosynthesis and assembly (qoxABCD,cydAB,hemABCX), anaerobic metabolism (pflAB,adhE,nrdDG), iron-sulfur cluster repair (scdA), and NO· detoxification (hmp). Targeted mutations in SrrAB-regulated loci show thathmpandqoxABCDare required for NO· resistance, whereasnrdDGis specifically required for anaerobic growth. We also show that SrrAB is required for survival in static biofilms, most likely due to oxygen limitation. Activation by hypoxia, NO·, or aqoxABCDquinol oxidase mutation suggests that the SrrAB TCS senses impaired electron flow in the electron transport chain rather than directly interacting with NO· in the manner of NsrR. Nevertheless, like NsrR, SrrAB achieves the physiological goals of selectively expressinghmpin the presence of NO· and minimizing the potential for Fenton chemistry. Activation of the SrrAB regulon allowsS. aureusto maintain energy production and essential biosynthetic processes, repair damage, and detoxify NO· in diverse host environments.IMPORTANCEThe Hmp flavohemoglobin is required for nitric oxide resistance and is widely distributed in bacteria. Hmp expression must be tightly regulated, because expression under aerobic conditions in the absence of nitric oxide can exacerbate oxidative stress. In most organisms,hmpexpression is controlled by the Fe-S cluster-containing repressor NsrR, but this transcriptional regulator is absent in the human pathogenStaphylococcus aureus. We show here thatS. aureusachieveshmpregulation in response to nitric oxide and oxygen limitation by placing it under the control of the SrrAB two-component system, which senses reduced electron flow through the respiratory chain. This provides a striking example of convergent evolution, in which the common physiological goals of responding to nitrosative stress while minimizing Fenton chemistry are achieved by distinct regulatory mechanisms.

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