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 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 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 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 The Staphylococcus aureus ArlRS two‐component system regulates virulence factor expression through MgrA

2019 ◽  
Vol 113 (1) ◽  
pp. 103-122 ◽  
Author(s):  
Heidi A. Crosby ◽  
Nitija Tiwari ◽  
Jakub M. Kwiecinski ◽  
Zhen Xu ◽  
Allison Dykstra ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factor ◽  
Two Component System ◽  
Component System ◽  
Two Component ◽  
Factor Expression

scholarly journals Phosphatidylinositol-Specific Phospholipase C Contributes to Survival of Staphylococcus aureus USA300 in Human Blood and Neutrophils

2014 ◽  
Vol 82 (4) ◽  
pp. 1559-1571 ◽  
Author(s):  
Mark J. White ◽  
Jeffrey M. Boyd ◽  
Alexander R. Horswill ◽  
William M. Nauseef
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Phospholipase C ◽  
Whole Blood ◽  
Dependent Manner ◽  
Binding Studies ◽  
Content Type ◽  
Positive Regulators

ABSTRACTStaphylococcus aureusis an important human pathogen that employs a large repertoire of secreted virulence factors to promote disease pathogenesis. Many strains ofS. aureuspossess aplcgene that encodes a phosphatidylinositol (PI)-specific phospholipase C (PI-PLC) capable of hydrolyzing PI and cleaving glycosyl-PI (GPI)-linked proteins from cell surfaces. Despite being secreted by virulent staphylococci, the contribution of PI-PLC to the capacity ofS. aureusto cause disease remains undefined. Our goal in these studies was to understand PI-PLC in the context ofS. aureusbiology. Among a collection of genetically diverse clinical isolates ofS. aureus, community-associated methicillin-resistantS. aureus(CA-MRSA) USA300 secreted the most PI-PLC. Screening a collection of two-component system (TCS) mutants ofS. aureus, we identified both theagrquorum-sensing system and the SrrAB TCS to be positive regulators ofplcgene expression. Real-time PCR and PI-PLC enzyme assays of the TCS mutants, coupled with SrrA promoter binding studies, demonstrated that SrrAB was the predominant transcriptional activator ofplc. Furthermore,plcregulation was linked to oxidative stress bothin vitroandin vivoin a SrrAB-dependent manner. A Δplcmutant in a CA-MRSA USA300 background exhibited a survival defect in human whole blood and in isolated neutrophils. However, the same mutant strain displayed no survival defect in murine models of infection or murine whole blood. Overall, these data identify potential links between bacterial responses to the host innate immune system and to oxidative stress and suggest how PI-PLC could contribute to the pathogenesis ofS. aureusinfections.

scholarly journals RegA, the Regulator of the Two-Component System RegB/RegA of Brucella suis, Is a Controller of Both Oxidative Respiration and Denitrification Required for Chronic Infection in Mice

2013 ◽  
Vol 81 (6) ◽  
pp. 2053-2061 ◽  
Author(s):  
Elias Abdou ◽  
Amélie Deredjian ◽  
María Pilar Jiménez de Bagüés ◽  
Stephan Köhler ◽  
Véronique Jubier-Maurin
Keyword(s):  
Oxygen Deficiency ◽  
Transcriptional Regulator ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Ubiquinol Oxidase ◽  
Two Component ◽  
Brucella Suis ◽  
Oxidative Respiration

ABSTRACTAdaptation to oxygen deficiency is essential for virulence and persistence ofBrucellainside the host. The flexibility of this bacterium with respect to oxygen depletion is remarkable, sinceBrucella suiscan use an oxygen-dependent transcriptional regulator of the FnrN family, two high-oxygen-affinity terminal oxidases, and a complete denitrification pathway to resist various conditions of oxygen deficiency. Moreover, our previous results suggested that oxidative respiration and denitrification can be simultaneously used byB. suisunder microaerobiosis. The requirement of a functional cytochromebdubiquinol oxidase for nitrite reductase expression evidenced the linkage of these two pathways, and the central role of the two-component system RegB/RegA in the coordinated control of both respiratory systems was demonstrated. We propose a scheme for global regulation ofB. suisrespiratory pathways by the transcriptional regulator RegA, which postulates a role for the cytochromebdubiquinol oxidase in redox signal transmission to the histidine sensor kinase RegB. More importantly, RegA was found to be essential forB. suispersistencein vivowithin oxygen-limited target organs. It is conceivable that RegA acts as a controller of numerous systems involved in the establishment of the persistent state, characteristic of chronic infections byBrucella.

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 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 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.

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