Adhesin competence repressor (AdcR) from Streptococcus pyogenes controls adaptive responses to zinc limitation and contributes to virulence

Sanson, Misu A.; Makthal, Nishanth; Flores, Anthony R.; Olsen, Randall J.; Musser, James M.; Kumaraswami, Muthiah

doi:10.1093/nar/gku1304

Cited by 59 publications

(89 citation statements)

References 59 publications

(94 reference statements)

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“…We have shown that the expression of the lmb, adcA, and adcAII genes is zinc dependent. Zn 2ϩ -dependent regulation is mediated in S. pneumoniae and S. pyogenes by the AdcR regulator (26,27,42). S. pneumoniae AdcR has a unique effector in zinc, and its crystal structure revealed the presence of two metal-binding sites (43).…”

Section: Resultsmentioning

confidence: 99%

The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival

et al. 2016

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The Lmb protein of Streptococcus agalactiae is described as an adhesin that binds laminin, a component of the human extracellular matrix. In this study, we revealed a new role for this protein in zinc uptake. We also identified two Lmb homologs, AdcA and AdcAII, redundant binding proteins that combine with the AdcCB translocon to form a zinc-ABC transporter. Expression of this transporter is controlled by the zinc concentration in the medium through the zinc-dependent regulator AdcR. Triple deletion of lmb, adcA, and adcAII, or that of the adcCB genes, impaired growth and cell separation in a zinc-restricted environment. Moreover, we found that this Adc zinc-ABC transporter promotes S. agalactiae growth and survival in some human biological fluids, suggesting that it contributes to the infection process. These results indicated that zinc has biologically vital functions in S. agalactiae and that, under the conditions tested, the Adc/Lmb transporter constitutes the main zinc acquisition system of the bacterium. IMPORTANCEA zinc transporter, composed of three redundant binding proteins (Lmb, AdcA, and AdcAII), was characterized in Streptococcus agalactiae. This system was shown to be essential for bacterial growth and morphology in zinc-restricted environments, including human biological fluids. S treptococcus agalactiae (group B streptococcus [GBS]) is aGram-positive commensal bacterium of the human gastrointestinal and uro-genital tracts. GBS carriage is mostly asymptomatic in healthy adults, and this bacterium is detected in the vagina of approximatively 30% of pregnant women. Maternal carriage is the main source of transmission to neonates, in which S. agalactiae can cause invasive infections (pneumonia, septicemia, and meningitis), with an overall mortality rate of approximately 10% (1, 2). GBS is also an emergent pathogen among the elderly and in adults with underlying diseases (1, 3).The ability of GBS to colonize different niches and cause infection is multifactorial, and many virulence-associated proteins have been identified (4, 5). Binding of GBS adhesins to components of the extracellular matrix constitutes a crucial first step in the process of infection (6-9). Among them, the Lmb protein has been identified as a GBS receptor for laminin, a glycosylated multidomain protein found in all human tissues (10). The gene encoding Lmb is located on a transposon with the scpB and sht genes, which encode a C5a peptidase and a histidine triad protein, respectively (11, 12). The lmb promoter region is a hot spot for the integration of two mobile genetic elements. One of them is associated with increased expression of lmb, resulting in increased binding of strains harboring the transposon to laminin (13). It has also been shown that Lmb may promote bacterial invasion in human brain microvascular endothelial cell lines (14).Lmb is clustered by sequence homology as a metal-binding receptor. Indeed, Lmb has strong homology with the zinc-binding proteins AdcA and Lbp of other streptococcal species (15, 16). Th...

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Section: Resultsmentioning

confidence: 99%

The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival

et al. 2016

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“…GAS strains were grown in THY, and cells were harvested by centrifugation at either ME or early stationary (ES) phase of growth. RNA isolation, RNA purification, rRNA depletion, and the development of adapter-tagged cDNA libraries were performed as previously described (26). cDNA libraries were run on an Illumina HiSeq 2000 to obtain 51-bp reads, and the reads were subsequently mapped to the reference serotype M3 genome using the CLC Genomics Workbench, version 8 (Qiagen).…”

Section: Methodsmentioning

confidence: 99%

A Single Amino Acid Replacement in the Sensor Kinase LiaS Contributes to a Carrier Phenotype in Group A Streptococcus

et al. 2015

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bDespite the high frequency of asymptomatic carriage of bacterial pathogens, we understand little about the bacterial molecular genetic underpinnings of this phenomenon. To obtain new information about the molecular genetic mechanisms underlying carriage of group A Streptococcus (GAS), we performed whole-genome sequencing of GAS strains recovered from a single individual during acute pharyngitis and subsequent asymptomatic carriage. We discovered that compared to the initial infection isolate, the strain recovered during asymptomatic carriage contained three single nucleotide polymorphisms, one of which was in a highly conserved region of a gene encoding a sensor kinase, liaS, resulting in an arginine-to-glycine amino acid replacement at position 135 of LiaS (LiaS R135G ). Using gene replacement, we demonstrate that introduction of the carrier allele (liaS R135G ) into a serotype-matched invasive strain increased mouse nasopharyngeal colonization and adherence to cultured human epithelial cells. The carrier mutation also resulted in a reduced ability to grow in human blood and reduced virulence in a mouse model of necrotizing fasciitis. Repair of the mutation in the GAS carrier strain restored virulence and decreased adherence to cultured human epithelial cells. We also provide evidence that the carrier mutation alters the GAS transcriptome, including altered transcription of GAS virulence genes, providing a potential mechanism for the pleiotropic phenotypic effects. Our data obtained using isogenic strains suggest that the liaS R135G mutation in the carrier strain contributes to the transition from disease to asymptomatic carriage and provides new information about this poorly described regulatory system in GAS. H uman bacterial pathogens, including Neisseria meningitidis(1), Staphylococcus aureus (2), Streptococcus pneumoniae (3), and Streptococcus pyogenes (group A Streptococcus [GAS]) (4), are frequently carried asymptomatically. However, in contrast to the relatively sophisticated knowledge regarding how bacterial pathogens cause disease, we understand little of the processes used by bacteria to persist on mucosal surfaces in the absence of symptoms. Asymptomatic carriage by or colonization of a susceptible host is a key step in the development of a myriad of diseases caused by bacterial pathogens. Inhibiting the ability of a pathogen to colonize a host may severely hamper its ability to subsequently cause disease. For example, vaccination against S. pneumoniae reduces the potential for disease by interfering with the organism's ability to colonize mucosal surfaces (5). In contrast, no effective GAS vaccine exists, and the ability of current candidate GAS vaccine formulations to prevent colonization is unknown. Thus, enhancing our understanding of the mechanisms used to colonize human hosts is paramount to reducing the incidence of disease caused by bacterial pathogens.GAS is an ideal model organism for the study of bacterial asymptomatic carriage. GAS causes a broad range of diseases in humans, including s...

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“…The gene Spy_0124 (sloR), encoding a regulator involved in metal homeostasis, was also significantly upregulated by 10.3-fold in the fabT deletion mutant during mid-exponential phase at 35°C. Metalloregulators have been shown to modulate virulence gene expression in S. pyogenes (49)(50)(51).…”

Section: Identification Of Acquired Polymorphisms In Serotype M1 Stramentioning

confidence: 99%

Genomic Landscape of Intrahost Variation in Group A Streptococcus: Repeated and Abundant Mutational Inactivation of the fabT Gene Encoding a Regulator of Fatty Acid Synthesis

et al. 2016

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dTo obtain new information about Streptococcus pyogenes intrahost genetic variation during invasive infection, we sequenced the genomes of 2,954 serotype M1 strains recovered from a nonhuman primate experimental model of necrotizing fasciitis. A total of 644 strains (21.8%) acquired polymorphisms relative to the input parental strain. The fabT gene, encoding a transcriptional regulator of fatty acid biosynthesis genes, contained 54.5% of these changes. The great majority of polymorphisms were predicted to deleteriously alter FabT function. Transcriptome-sequencing (RNA-seq) analysis of a wild-type strain and an isogenic fabT deletion mutant strain found that between 3.7 and 28.5% of the S. pyogenes transcripts were differentially expressed, depending on the growth temperature (35°C or 40°C) and growth phase (mid-exponential or stationary phase). Genes implicated in fatty acid synthesis and lipid metabolism were significantly upregulated in the fabT deletion mutant strain. FabT also directly or indirectly regulated central carbon metabolism genes, including pyruvate hub enzymes and fermentation pathways and virulence genes. Deletion of fabT decreased virulence in a nonhuman primate model of necrotizing fasciitis. In addition, the fabT deletion strain had significantly decreased survival in human whole blood and during phagocytic interaction with polymorphonuclear leukocytes ex vivo. We conclude that FabT mutant progeny arise during infection, constitute a metabolically distinct subpopulation, and are less virulent in the experimental models used here. Streptococcus pyogenes is a Gram-positive bacterium that causes a range of diseases in humans, including pharyngitis, superficial and deep skin infections, acute rheumatic fever, poststreptococcal glomerulonephritis, bacteremia, and necrotizing fasciitis ("flesh-eating disease") (1, 2). Globally, there are over 700 million group A streptococcus (GAS) infections annually (3). It has been estimated that 9,000 to 11,500 cases of invasive GAS disease occur each year in the United States, resulting in 1,000 to 1,800 deaths annually (4; http://www.cdc.gov). Rheumatic fever, necrotizing fasciitis, and toxic shock syndrome are responsible for the high morbidity and mortality rates due to GAS infections (5).Advances in DNA sequencing and related technologies have facilitated genome-wide dissection of genetic events involved in colonization (6), immune evasion (7), virulence (8-10), and the evolution and spread of highly virulent S. pyogenes clones (11-13). To advance our understanding of S. pyogenes molecular-pathogenesis events occurring during invasive infection, we performed whole-genome sequencing of 2,954 isolates recovered from a nonhuman primate model of necrotizing fasciitis. The resulting genome sequence data stimulated us to construct an isogenic fabT deletion mutant strain and to compare its global transcriptome and virulence attributes with those of the wild-type parental strain. MATERIALS AND METHODSBacterial strains and growth conditions. Escherichia coli strai...

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Adhesin competence repressor (AdcR) from Streptococcus pyogenes controls adaptive responses to zinc limitation and contributes to virulence

Cited by 59 publications

References 59 publications

The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival

The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival

A Single Amino Acid Replacement in the Sensor Kinase LiaS Contributes to a Carrier Phenotype in Group A Streptococcus

Genomic Landscape of Intrahost Variation in Group A Streptococcus: Repeated and Abundant Mutational Inactivation of the fabT Gene Encoding a Regulator of Fatty Acid Synthesis

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