Yersiniabactin contributes to overcoming zinc restriction during Yersinia pestis infection of mammalian and insect hosts

2021 ◽  
Vol 118 (44) ◽  
pp. e2104073118
Author(s):  
Sarah L. Price ◽  
Viveka Vadyvaloo ◽  
Jennifer K. DeMarco ◽  
Amanda Brady ◽  
Phoenix A. Gray ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Iron Acquisition ◽  
Mammalian Host ◽  
Independent Manner ◽  
Transmission Cycle ◽  
Nutritional Immunity ◽  
Lethal Infection ◽  
Bacterial Mutants ◽  
Bona Fide ◽  
Key Barrier

Yersinia pestis causes human plague and colonizes both a mammalian host and a flea vector during its transmission cycle. A key barrier to bacterial infection is the host’s ability to actively sequester key biometals (e.g., iron, zinc, and manganese) required for bacterial growth. This is referred to as nutritional immunity. Mechanisms to overcome nutritional immunity are essential virulence factors for bacterial pathogens. Y. pestis produces an iron-scavenging siderophore called yersiniabactin (Ybt) that is required to overcome iron-mediated nutritional immunity and cause lethal infection. Recently, Ybt has been shown to bind to zinc, and in the absence of the zinc transporter ZnuABC, Ybt improves Y. pestis growth in zinc-limited medium. These data suggest that, in addition to iron acquisition, Ybt may also contribute to overcoming zinc-mediated nutritional immunity. To test this hypothesis, we used a mouse model defective in iron-mediated nutritional immunity to demonstrate that Ybt contributes to virulence in an iron-independent manner. Furthermore, using a combination of bacterial mutants and mice defective in zinc-mediated nutritional immunity, we identified calprotectin as the primary barrier for Y. pestis to acquire zinc during infection and that Y. pestis uses Ybt to compete with calprotectin for zinc. Finally, we discovered that Y. pestis encounters zinc limitation within the flea midgut, and Ybt contributes to overcoming this limitation. Together, these results demonstrate that Ybt is a bona fide zinc acquisition mechanism used by Y. pestis to surmount zinc limitation during the infection of both the mammalian and insect hosts.

scholarly journals Candida albicans Ferric Reductases Are Differentially Regulated in Response to Distinct Forms of Iron Limitation by the Rim101 and CBF Transcription Factors

2008 ◽  
Vol 7 (7) ◽  
pp. 1168-1179 ◽  
Author(s):  
Yong-Un Baek ◽  
Mingchun Li ◽  
Dana A. Davis
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Transcription Factors ◽  
Iron Acquisition ◽  
Mammalian Host ◽  
Regulatory Sequence ◽  
Ferric Reductase ◽  
Reductase Gene ◽  
Ferric Reductases

ABSTRACT Iron is an essential nutrient that is severely limited in the mammalian host. Candida albicans encodes a family of 15 putative ferric reductases, which are required for iron acquisition and utilization. Despite the central role of ferric reductases in iron acquisition and mobilization, relatively little is known about the regulatory networks that govern ferric reductase gene expression in C. albicans. Here we have demonstrated the differential regulation of two ferric reductases, FRE2 and FRP1, in response to distinct iron-limited environments. FRE2 and FRP1 are both induced in alkaline-pH environments directly by the Rim101 transcription factor. However, FRP1 but not FRE2 is also induced by iron chelation. We have identified a CCAAT motif as the critical regulatory sequence for chelator-mediated induction and have found that the CCAAT binding factor (CBF) is essential for FRP1 expression in iron-limited environments. We found that a hap5Δ/hap5Δ mutant, which disrupts the core DNA binding activity of CBF, is unable to grow under iron-limited conditions. C. albicans encodes three CBF-dependent transcription factors, and we identified the Hap43 protein as the CBF-dependent transcription factor required for iron-limited responses. These studies provide key insights into the regulation of ferric reductase gene expression in the fungal pathogen C. albicans.

scholarly journals Loss of RASSF2 Enhances Tumorigencity of Lung Cancer Cells and Confers Resistance to Chemotherapy

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jennifer Clark ◽  
Jessica Freeman ◽  
Howard Donninger
Keyword(s):  
Lung Cancer ◽  
Cancer Cells ◽  
Morphological Changes ◽  
Lung Cancer Cells ◽  
Ras Signaling ◽  
Independent Manner ◽  
Primary Tumors ◽  
Bona Fide ◽  
Proliferation And Invasion ◽  
Resistance To Chemotherapy

RASSF2 is a novel pro-apoptotic effector of K-Ras that is frequently inactivated in a variety of primary tumors by promoter methylation. Inactivation of RASSF2 enhances K-Ras-mediated transformation and overexpression of RASSF2 suppresses tumor cell growth. In this study, we confirm that RASSF2 and K-Ras form an endogenous complex, validating that RASSF2 is a bona fide K-Ras effector. We adopted an RNAi approach to determine the effects of inactivation of RASSF2 on the transformed phenotype of lung cancer cells containing an oncogenic K-Ras. Loss of RASSF2 expression resulted in a more aggressive phenotype that was characterized by enhanced cell proliferation and invasion, decreased cell adhesion, the ability to grow in an anchorage-independent manner and cell morphological changes. This enhanced transformed phenotype of the cells correlated with increased levels of activated AKT, indicating that RASSF2 can modulate Ras signaling pathways. Loss of RASSF2 expression also confers resistance to taxol and cisplatin, two frontline therapeutics for the treatment of lung cancer. Thus we have shown that inactivation of RASSF2, a process that occurs frequently in primary tumors, enhances the transforming potential of activated K-Ras and our data suggests that RASSF2 may be a novel candidate for epigenetic-based therapy in lung cancer.

scholarly journals Yersinia pestis Targets the Host Endosome Recycling Pathway during the Biogenesis of the Yersinia-Containing Vacuole To Avoid Killing by Macrophages

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael G. Connor ◽  
Amanda R. Pulsifer ◽  
Donghoon Chung ◽  
Eric C. Rouchka ◽  
Brian K. Ceresa ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Host Factors ◽  
Endocytic Recycling ◽  
Recycling Endosome ◽  
Independent Manner ◽  
Genome Wide ◽  
Type Three Secretion System ◽  
A Genome ◽  
Recycling Pathway ◽  
Bacterial Replication

ABSTRACTYersinia pestishas evolved many strategies to evade the innate immune system. One of these strategies is the ability to survive within macrophages. Upon phagocytosis,Y. pestisprevents phagolysosome maturation and establishes a modified compartment termed theYersinia-containing vacuole (YCV).Y. pestisactively inhibits the acidification of this compartment, and eventually, the YCV transitions from a tight-fitting vacuole into a spacious replicative vacuole. The mechanisms to generate the YCV have not been defined. However, we hypothesized that YCV biogenesis requiresY. pestisinteractions with specific host factors to subvert normal vesicular trafficking. In order to identify these factors, we performed a genome-wide RNA interference (RNAi) screen to identify host factors required forY. pestissurvival in macrophages. This screen revealed that 71 host proteins are required for intracellular survival ofY. pestis. Of particular interest was the enrichment for genes involved in endosome recycling. Moreover, we demonstrated thatY. pestisactively recruits Rab4a and Rab11b to the YCV in a type three secretion system-independent manner, indicating remodeling of the YCV byY. pestisto resemble a recycling endosome. While recruitment of Rab4a was necessary to inhibit YCV acidification and lysosomal fusion early during infection, Rab11b appeared to contribute to later stages of YCV biogenesis. We also discovered thatY. pestisdisrupts global host endocytic recycling in macrophages, possibly through sequestration of Rab11b, and this process is required for bacterial replication. These data provide the first evidence thatY. pestistargets the host endocytic recycling pathway to avoid phagolysosomal maturation and generate the YCV.IMPORTANCEYersinia pestiscan infect and survive within macrophages. However, the mechanisms that the bacterium use to subvert killing by these phagocytes have not been defined. To provide a better understanding of these mechanisms, we used an RNAi approach to identify host factors required for intracellularY. pestissurvival. This approach revealed that the host endocytic recycling pathway is essential forY. pestisto avoid clearance by the macrophage. We further demonstrate thatY. pestisremodels the phagosome to resemble a recycling endosome, allowing the bacterium to avoid the normal phagolysosomal maturation pathway. Moreover, we show that infection withY. pestisdisrupts normal recycling in the macrophage and that disruption is required for bacterial replication. These findings provide the first evidence thatY. pestistargets the host endocytic recycling pathway in order to evade killing by macrophages.

scholarly journals Iron acquisition in plague: modular logic in enzymatic biogenesis of yersiniabactin by Yersinia pestis

1998 ◽  
Vol 5 (10) ◽  
pp. 573-586 ◽  
Author(s):  
Amy M. Gehring ◽  
Edward DeMoll ◽  
Jacqueline D. Fetherston ◽  
Ichiro Mori ◽  
George F. Mayhew ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Iron Acquisition ◽  
Modular Logic

scholarly journals The Iron Tug-of-War between Bacterial Siderophores and Innate Immunity

2019 ◽  
Vol 11 (3) ◽  
pp. 249-262 ◽  
Author(s):  
Rachel Golonka ◽  
Beng San Yeoh ◽  
Matam Vijay-Kumar
Keyword(s):  
Innate Immunity ◽  
Pathogenic Bacteria ◽  
Binding Proteins ◽  
Mammalian Host ◽  
Lipocalin 2 ◽  
Nutritional Immunity ◽  
Iron Sulfur ◽  
Ribonucleotide Reductases ◽  
Iron Binding Proteins ◽  
Almost All

Iron is necessary for the survival of almost all aerobic organisms. In the mammalian host, iron is a required cofactor for the assembly of functional iron-sulfur (Fe-S) cluster proteins, heme-binding proteins and ribonucleotide reductases that regulate various functions, including heme synthesis, oxygen transport and DNA synthesis. However, the bioavailability of iron is low due to its insolubility under aerobic conditions. Moreover, the host coordinates a nutritional immune response to restrict the accessibility of iron against potential pathogens. To counter nutritional immunity, most commensal and pathogenic bacteria synthesize and secrete small iron chelators termed siderophores. Siderophores have potent affinity for iron, which allows them to seize the essential metal from the host iron-binding proteins. To safeguard against iron thievery, the host relies upon the innate immune protein, lipocalin 2 (Lcn2), which could sequester catecholate-type siderophores and thus impede bacterial growth. However, certain bacteria are capable of outmaneuvering the host by either producing “stealth” siderophores or by expressing competitive antagonists that bind Lcn2 in lieu of siderophores. In this review, we summarize the mechanisms underlying the complex iron tug-of-war between host and bacteria with an emphasis on how host innate immunity responds to siderophores.

scholarly journals Poly-N-Acetylglucosamine Expression by Wild-Type Yersinia pestis Is Maximal at Mammalian, Not Flea, Temperatures

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Pauline Yoong ◽  
Colette Cywes-Bentley ◽  
Gerald B. Pier
Keyword(s):  
Yersinia Pestis ◽  
Congo Red ◽  
Biofilm Formation ◽  
Mammalian Host ◽  
Virulence Plasmid ◽  
Insect Vector ◽  
Wild Type ◽  
Content Type ◽  
Higher Temperature ◽  
Mammalian Infection

ABSTRACTNumerous bacteria, includingYersinia pestis, express the poly-N-acetylglucosamine (PNAG) surface carbohydrate, a major component of biofilms often associated with a specific appearance of colonies on Congo red agar. Biofilm formation and PNAG synthesis byY. pestishave been reported to be maximal at 21 to 28°C or “flea temperatures,” facilitating the regurgitation ofY. pestisinto a mammalian host during feeding, but production is diminished at 37°C and thus presumed to be decreased during mammalian infection. Most studies of PNAG expression and biofilm formation byY. pestishave used a low-virulence derivative of strain KIM, designated KIM6+, that lacks the pCD1 virulence plasmid, and an isogenic mutant without the pigmentation locus, which contains the hemin storage genes that encode PNAG biosynthetic proteins. Using confocal microscopy, fluorescence-activated cell sorter analysis and growth on Congo red agar, we confirmed prior findings regarding PNAG production with the KIM6+ strain. However, we found that fully virulent wild-type (WT) strains KIM and CO92 had maximal PNAG expression at 37°C, with lower PNAG production at 28°C both in broth medium and on Congo red agar plates. Notably, the typical dark colony morphology appearing on Congo red agar was maintained at 28°C, indicating that this phenotype is not associated with PNAG expression in WTY. pestis. Extracts of WT sylvaticY. pestisstrains from the Russian Federation confirmed the maximal expression of PNAG at 37°C. PNAG production by WTY. pestisis maximal at mammalian and not insect vector temperatures, suggesting that this factor may have a role during mammalian infection.IMPORTANCEYersinia pestistransitions from low-temperature residence and replication in insect vectors to higher-temperature replication in mammalian hosts. Prior findings based primarily on an avirulent derivative of WT (wild-type) KIM, named KIM6+, showed that biofilm formation associated with synthesis of poly-N-acetylglucosamine (PNAG) is maximal at 21 to 28°C and decreased at 37°C. Biofilm formation was purported to facilitate the transmission ofY. pestisfrom fleas to mammals while having little importance in mammalian infection. Here we found that for WT strains KIM and CO92, maximal PNAG production occurs at 37°C, indicating that temperature regulation of PNAG production in WTY. pestisis not mimicked by strain KIM6+. Additionally, we found that Congo red binding does not always correlate with PNAG production, despite its widespread use as an indicator of biofilm production. Taken together, the findings show that a role for PNAG in WTY. pestisinfection should not be disregarded and warrants further study.

scholarly journals The Metallophore Staphylopine Enables Staphylococcus aureus To Compete with the Host for Zinc and Overcome Nutritional Immunity

mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Kyle P. Grim ◽  
Brian San Francisco ◽  
Jana N. Radin ◽  
Erin B. Brazel ◽  
Jessica L. Kelliher ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Defense ◽  
Iron Acquisition ◽  
Essential Metals ◽  
Immune Effector ◽  
Essential Metal ◽  
Zinc Availability ◽  
Nutritional Immunity ◽  
New Family ◽  
New Type

ABSTRACT During infection, the host sequesters essential nutrients, such as zinc, to combat invading microbes. Despite the ability of the immune effector protein calprotectin to bind zinc with subpicomolar affinity, Staphylococcus aureus is able to successfully compete with the host for zinc. However, the zinc importers expressed by S. aureus remain unknown. Our investigations have revealed that S. aureus possesses two importers, AdcABC and CntABCDF, which are induced in response to zinc limitation. While AdcABC is similar to known zinc importers in other bacteria, CntABCDF has not previously been associated with zinc acquisition. Concurrent loss of the two systems severely impairs the ability of S. aureus to obtain zinc and grow in zinc-limited environments. Further investigations revealed that the Cnt system is responsible for the ability of S. aureus to compete with calprotectin for zinc in culture and contributes to acquisition of zinc during infection. The cnt locus also enables S. aureus to produce the broad-spectrum metallophore staphylopine. Similarly to the Cnt transporter, loss of staphylopine severely impairs the ability of S. aureus to resist host-imposed zinc starvation, both in culture and during infection. Further investigations revealed that together staphylopine and the Cnt importer function analogously to siderophore-based iron acquisition systems in order to facilitate zinc acquisition by S. aureus. Analogous systems are found in a broad range of Gram-positive and Gram-negative bacterial pathogens, suggesting that this new type of zinc importer broadly contributes to the ability of bacteria to cause infection. IMPORTANCE A critical host defense against infection is the restriction of zinc availability. Despite the subpicomolar affinity of the immune effector calprotectin for zinc, Staphylococcus aureus can successfully compete for this essential metal. Here, we describe two zinc importers, AdcABC and CntABCDF, possessed by S. aureus, the latter of which has not previously been associated with zinc acquisition. The ability of S. aureus to compete with the host for zinc is dependent on CntABCDF and the metallophore staphylopine, both in culture and during infection. These results expand the mechanisms utilized by bacteria to obtain zinc, beyond Adc-like systems, and demonstrate that pathogens utilize strategies similar to siderophore-based iron acquisition to obtain other essential metals during infection. The staphylopine synthesis machinery is present in a diverse collection of bacteria, suggesting that this new family of zinc importers broadly contributes to the ability of numerous pathogens to cause infection. IMPORTANCE A critical host defense against infection is the restriction of zinc availability. Despite the subpicomolar affinity of the immune effector calprotectin for zinc, Staphylococcus aureus can successfully compete for this essential metal. Here, we describe two zinc importers, AdcABC and CntABCDF, possessed by S. aureus, the latter of which has not previously been associated with zinc acquisition. The ability of S. aureus to compete with the host for zinc is dependent on CntABCDF and the metallophore staphylopine, both in culture and during infection. These results expand the mechanisms utilized by bacteria to obtain zinc, beyond Adc-like systems, and demonstrate that pathogens utilize strategies similar to siderophore-based iron acquisition to obtain other essential metals during infection. The staphylopine synthesis machinery is present in a diverse collection of bacteria, suggesting that this new family of zinc importers broadly contributes to the ability of numerous pathogens to cause infection.

Yersinia pestis and plague

2003 ◽  
Vol 31 (1) ◽  
pp. 104-107 ◽  
Author(s):  
R.W. Titball ◽  
J. Hill ◽  
D.G. Lawton ◽  
K.A. Brown
Keyword(s):  
Host Cell ◽  
Yersinia Pestis ◽  
Genome Sequence ◽  
Yersinia Pseudotuberculosis ◽  
Cell Types ◽  
Mammalian Host ◽  
Aetiological Agent ◽  
Mild Disease ◽  
Regulatory Systems ◽  
Obligate Pathogen

Yersinia pestis is the aetiological agent of plague, a disease of humans that has potentially devastating consequences. Evidence indicates that Y. pestis evolved from Yersinia pseudotuberculosis, an enteric pathogen that normally causes a relatively mild disease. Although Y. pestis is considered to be an obligate pathogen, the lifestyle of this organism is surprisingly complex. The bacteria are normally transmitted to humans from a flea vector, and Y. pestis has a number of mechanisms which allow survival in the flea. Initially, the bacteria have an intracellular lifestyle in the mammalian host, surviving in macrophages. Later, the bacteria adopt an extracellular lifestyle. These different interactions with different host cell types are regulated by a number of systems, which are not well characterized. The availability of the genome sequence for this pathogen should now allow a systematic dissection of these regulatory systems.

scholarly journals Deletion of Yersinia pestis ail causes temperature sensitive pleiotropic effects including cell lysis that are suppressed by carbon source, cations, or loss of phospholipase A activity

2021 ◽  
Author(s):  
Anna M. Kolodziejek ◽  
Carolyn J. Hovde ◽  
Gregory A. Bohach ◽  
Scott A. Minnich
Keyword(s):  
Heat Shock ◽  
Yersinia Pestis ◽  
Outer Membrane ◽  
Pleiotropic Effects ◽  
Phospholipase A ◽  
Lipid Homeostasis ◽  
Mammalian Host ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Gram Negative

Maintenance of phospholipid (PL) and lipopoly- or lipooligo-saccharide (LPS or LOS) asymmetry in the outer membrane (OM) of Gram-negative bacteria is essential but poorly understood. The Yersinia pestis OM Ail protein was required to maintain lipid homeostasis and cell integrity at elevated temperature (37° C). Loss of this protein had pleiotropic effects. A Y. pestis Δail mutant and KIM6 + wild- type were systematically compared for (i) growth requirements at 37° C, (ii) cell structure, (iii) antibiotic and detergent sensitivity, (iv) proteins released into supernates, (v) induction of the heat shock response, and (vi) physiological and genetic suppressors that restored the wild- type phenotype. The Δail mutant grew normally at 28° C but lysed at 37° C when it entered stationary phase as shown by cell count, SDS-PAGE of cell supernatants, and electron microscopy. Immuno-fluorescent microscopy showed that the Δail mutant did not assemble Caf1 capsule. Expression of heat shock promoters rpoE or rpoH fused to a lux operon reporter were not induced when the Δail mutant was shifted from the 28° C to 37° C (p<0.001 and p<0.01 respectively). Mutant lysis was suppressed by addition of 11 mM glucose, 22 or 44 mM glycerol, 2.5 mM Ca 2+ , or 2.5 mM Mg 2+ to the growth medium, or by a mutation in the phospholipase A gene ( pldA ::miniTn 5 , ΔpldA, or PldA S164A ). A model, accounting for the temperature-sensitive lysis of the Δail mutant and the Ail-dependent stabilization of the OM tetraacylated LOS at 37°C is presented. IMPORTANCE The Gram-negative pathogen, Yersinia pestis , transitions between a flea vector (ambient temperature) and a mammalian host (37° C). In response to 37° C, Y. pestis modifies its outer membrane (OM) by reducing the fatty acid content in lipid A, changing the outer leaflet from being predominantly hexaacylated to being predominantly tetraacylated. It also increases the Ail concentration, so it becomes the most prominent OM protein. Both measures are needed for Y. pestis to evade the host innate immune response. Deletion of ail destabilizes the OM at 37° C causing the cells to lyse. These results show that a protein is essential for maintaining lipid asymmetry and lipid homeostasis in the bacterial OM.

scholarly journals Expression and Immunological Analysis of the Plasmid-Borne mlp Genes of Borrelia burgdorferiStrain B31

2000 ◽  
Vol 68 (9) ◽  
pp. 4992-5001 ◽  
Author(s):  
Stephen F. Porcella ◽  
Cecily A. Fitzpatrick ◽  
James L. Bono
Keyword(s):  
Northern Blot Analysis ◽  
Temperature Shift ◽  
Gene Families ◽  
Mammalian Host ◽  
Transmission Cycle ◽  
Experimental Mouse ◽  
Infection Processes ◽  
Sigma 70 ◽  
Extension Analysis ◽  
Striking Contrast

ABSTRACT A lipoprotein gene family first identified in Borrelia burgdorferi strain 297, designated 2.9 LP and recently renamed mlp, was found on circular and linear plasmids in the genome sequence of B. burgdorferistrain B31-M1. Sequence analyses of the B31 mlp genes and physically linked variant gene families indicated that mlpgene heterogeneity is unique and unrelated to location or linkage to divergent sequences. Evidence of recombination between B31mlp alleles was also detected. Northern blot analysis of cultured strain B31 indicated that the mlp genes were not expressed at a temperature (23°C) characteristic of that of ticks in the environment. In striking contrast, expression of manymlp genes increased substantially when strain B31 was shifted to 35°C, a temperature change mimicking that occurring in the natural transmission cycle of the spirochete from tick to mammal. Primer extension analysis of the mlp mRNA transcripts suggested that sigma 70-like promoters are involved inmlp expression during temperature shift conditions. Antibodies were made against strain B31 Mlp proteins within the first 4 weeks after experimental mouse infection. Importantly, Lyme disease patients also had serum antibodies reactive with purified recombinant Mlp proteins from strain B31, a result indicating that humans are exposed to Mlp proteins during infection. Taken together, the data indicate that strain B31 mlp genes encode a diverse array of lipoproteins which may participate in early infection processes in the mammalian host.

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