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Lei B, Hanks TS, Bao Y, Liu M. Slipped-strand mispairing within a polycytidine tract in transcriptional regulator mga leads to M protein phase variation and Mga length polymorphism in Group A Streptococcus. Front Microbiol 2023; 14:1212149. [PMID: 37434706 PMCID: PMC10330708 DOI: 10.3389/fmicb.2023.1212149] [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] [Received: 04/26/2023] [Accepted: 06/06/2023] [Indexed: 07/13/2023] Open
Abstract
The M protein, a major virulence factor of Group A Streptococcus (GAS), is regulated by the multigene regulator Mga. An unexplained phenomena frequently occurring with in vitro genetic manipulation or culturing of M1T1 GAS strains is the loss of M protein production. This study was aimed at elucidating the basis for the loss of M protein production. The majority of M protein-negative (M-) variants had one C deletion at a tract of 8 cytidines starting at base 1,571 of the M1 mga gene, which is designated as c.1571C[8]. The C deletion led to a c.1571C[7] mga variant that has an open reading frame shift and encodes a Mga-M protein fusion protein. Transformation with a plasmid containing wild-type mga restored the production of the M protein in the c.1571C[7] mga variant. Isolates producing M protein (M+) were recovered following growth of the c.1571C[7] M protein-negative variant subcutaneously in mice. The majority of the recovered isolates with reestablished M protein production had reverted back from c.1571C[7] to c.1571C[8] tract and some M+ isolates lost another C in the c.1571C[7] tract, leading to a c.1571C[6] variant that encodes a functional Mga with 13 extra amino acid residues at the C-terminus compared with wild-type Mga. The nonfunctional c.1571C[7] and functional c.1571C[6] variants are present in M1, M12, M14, and M23 strains in NCBI genome databases, and a G-to-A nonsense mutation at base 1,657 of M12 c.1574C[7] mga leads to a functional c.1574C[7]/1657A mga variant and is common in clinical M12 isolates. The numbers of the C repeats in this polycytidine tract and the polymorphism at base 1,657 lead to polymorphism in the size of Mga among clinical isolates. These findings demonstrate the slipped-strand mispairing within the c.1574C[8] tract of mga as a reversible switch controlling M protein production phase variation in multiple GAS common M types.
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Affiliation(s)
- Benfang Lei
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Tracey S. Hanks
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Yunjuan Bao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Mengyao Liu
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
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Jing Y, Feng B, Gao J, Li J, Zhou G, Sun Z, Wang Y. BLAB2CancerKD: a knowledge graph database focusing on the association between lactic acid bacteria and cancer, but beyond. Database (Oxford) 2023; 2023:7176387. [PMID: 37221044 DOI: 10.1093/database/baad036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 04/23/2023] [Accepted: 04/28/2023] [Indexed: 05/25/2023]
Abstract
In a broad sense, lactic acid bacteria (LAB) is a general term for Gram-positive bacteria that can produce lactic acid by utilizing fermentable carbohydrates. It is widely used in essential fields such as industry, agriculture, animal husbandry and medicine. At the same time, LAB are closely related to human health. They can regulate human intestinal flora and improve gastrointestinal function and body immunity. Cancer, a disease in which some cells grow out of control and spread to other body parts, is one of the leading causes of human death worldwide. In recent years, the potential of LAB in cancer treatment has attracted attention. Mining knowledge from the scientific literature significantly accelerates its application in cancer treatment. Using 7794 literature studies of LAB cancer as source data, we have processed 16 543 biomedical concepts and 23 091 associations by using automatic text mining tools combined with manual curation of domain experts. An ontology containing 31 434 pieces of structured data is constructed. Finally, based on ontology, a knowledge graph (KG) database, which is called Beyond 'Lactic acid bacteria to Cancer Knowledge graph Database' (BLAB2CancerKD), is constructed by using KG and web technology. BLAB2CancerKD presents all the relevant knowledge intuitively and clearly in various data presentation forms, and the interactive system function also makes it more efficient. BLAB2CancerKD will be continuously updated to advance the research and application of LAB in cancer therapy. Researchers can visit BLAB2CancerKD at. Database URL http://110.40.139.2:18095/.
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Affiliation(s)
- Yi Jing
- Faculty of Science, The University of New South Wales, High Street, Sydney, New South Wales 2052, Australia
- Inner Mongolia Autonomous Region Key Laboratory of Big Data Research and Application for Agriculture and Animal Husbandry, Zhaowuda Road No. 306, Hohhot 010018, China
| | - Baiyang Feng
- Inner Mongolia Autonomous Region Key Laboratory of Big Data Research and Application for Agriculture and Animal Husbandry, Zhaowuda Road No. 306, Hohhot 010018, China
- College of Computer and Information Engineering, Inner Mongolia Agricultural University, Erdos East Street No. 29, Hohhot 010011, China
| | - Jing Gao
- Inner Mongolia Autonomous Region Key Laboratory of Big Data Research and Application for Agriculture and Animal Husbandry, Zhaowuda Road No. 306, Hohhot 010018, China
- College of Computer and Information Engineering, Inner Mongolia Agricultural University, Erdos East Street No. 29, Hohhot 010011, China
- Inner Mongolia Autonomous Region Big Data Center, Chilechuan Street No. 1, Hohhot 010091, China
| | - Jin Li
- Inner Mongolia Autonomous Region Key Laboratory of Big Data Research and Application for Agriculture and Animal Husbandry, Zhaowuda Road No. 306, Hohhot 010018, China
- College of Computer and Information Engineering, Inner Mongolia Agricultural University, Erdos East Street No. 29, Hohhot 010011, China
| | - Ganghui Zhou
- Inner Mongolia Autonomous Region Key Laboratory of Big Data Research and Application for Agriculture and Animal Husbandry, Zhaowuda Road No. 306, Hohhot 010018, China
- College of Computer and Information Engineering, Inner Mongolia Agricultural University, Erdos East Street No. 29, Hohhot 010011, China
| | - Zhihong Sun
- College of Food Science and Engineering, Inner Mongolia Agricultural University, Zhaowuda Road No. 306, Hohhot 010018, China
| | - Yufei Wang
- The Affiliated Hospital of Inner Mongolia Medical University, Tongdao North road No.1, Hohhot 010050, China
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The Streptococcus pyogenes signaling peptide SpoV regulates streptolysin O and enhances survival in murine blood. J Bacteriol 2021; 203:JB.00586-20. [PMID: 33722844 PMCID: PMC8117530 DOI: 10.1128/jb.00586-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus, GAS) is a human pathogen that causes a wide range of diseases. For successful colonization within a variety of host niches, GAS must sense and respond to environmental changes. Intercellular communication mediated by peptides is one way GAS coordinates gene expression in response to diverse environmental stressors, which enhances bacterial survival and contributes to virulence. Using peptidomics we identified SpoV (Streptococcal peptide controlling virulence) in culture supernatant fluids. SpoV is a secreted peptide encoded near the gene encoding the extracellular cholesterol-dependent cytolysin streptolysin O (slo) The addition of synthetic SpoV peptide derivatives, but not control peptides, increased slo transcript abundance in an M49 isolate but not in an M3 isolate. Deletion of spoV decreased slo transcript abundance, extracellular SLO protein levels, and SLO-specific hemolytic activity. Complementation of the spoV mutant increased slo transcript abundance. Lastly, a spoV mutant was deficient in the ability to survive in murine blood compared to the parental strain. Moreover, pre-incubation of the spoV mutant with synthetic SpoV peptide derivatives increased GAS survival. Our findings show that slo expression is regulated, in part, by the GAS-specific signaling peptide SpoV.IMPORTANCEGAS secretes signaling peptides that can alter gene expression and impact virulence. We used peptidomics to identify a signaling peptide designated SpoV. Further, we showed that SpoV altered the expression of the cholesterol-dependent cytolysin SLO. Peptide signaling plays an important regulatory role during disease progression among several bacterial pathogens, including GAS. The therapeutic potential of manipulating peptide-controlled regulatory networks is an attractive option for the development of novel therapeutic strategies that disrupt virulence gene expression.
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Colonization of the Murine Oropharynx by Streptococcus pyogenes Is Governed by the Rgg2/3 Quorum Sensing System. Infect Immun 2020; 88:IAI.00464-20. [PMID: 32747598 DOI: 10.1128/iai.00464-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Streptococcus pyogenes is a human-restricted pathogen most often found in the human nasopharynx. Multiple bacterial factors are known to contribute to persistent colonization of this niche, and many are important in mucosal immunity and vaccine development. In this work, mice were infected intranasally with transcriptional regulator mutants of the Rgg2/3 quorum sensing (QS) system-a peptide-based signaling system conserved in sequenced isolates of S. pyogenes Deletion of the QS system's transcriptional activator (Δrgg2) dramatically diminished the percentage of colonized mice, while deletion of the transcriptional repressor (Δrgg3) increased the percentage of colonized mice compared to that of the wild type (WT). Stimulation of the QS system using synthetic pheromones prior to inoculation did not significantly increase the percentage of animals colonized, indicating that QS-dependent colonization is responsive to the intrinsic conditions within the host upper respiratory tract. Bacterial RNA extracted directly from oropharyngeal swabs and evaluated by quantitative reverse transcription-PCR (qRT-PCR) subsequently confirmed QS upregulation within 1 h of inoculation. In the nasal-associated lymphoid tissue (NALT), a muted inflammatory response to the Δrgg2 bacteria suggests that their rapid elimination failed to elicit the previously characterized response to intranasal inoculation of GAS. This work identifies a new transcriptional regulatory system governing the ability of S. pyogenes to colonize the nasopharynx and provides knowledge that could help lead to decolonization therapeutics.
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Zhang X, Wei D, Zhao Y, Zhong Z, Wang Y, Song Y, Cai M, Zhang W, Zhao J, Lv C, Zhu H. Immunization With a Secreted Esterase Protects Mice Against Multiple Serotypes (M1, M3, and M28) of Group A Streptococcus. Front Microbiol 2020; 11:565. [PMID: 32308652 PMCID: PMC7145942 DOI: 10.3389/fmicb.2020.00565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/16/2020] [Indexed: 11/13/2022] Open
Abstract
Streptococcal secreted esterase (Sse) is a platelet-activating factor acetylhydrolase that is critical for Group A Streptococcus (GAS) skin invasion and innate immune evasion. There are two Sse variant complexes that share >98% identity within each complex but display about 37% variation between the complexes in amino acid sequences. Sse immunization protects mice against lethal infection and skin invasion in subcutaneous infection with the hypervirulent CovRS mutant strain, MGAS5005. However, it is not known whether Sse immunization provides significant protection against infection of GAS with functional CovRS and whether immunization with Sse of one variant complex provides protection against infection of GAS that produces Sse of another variant complex. This study was designed to address these questions. Mice were immunized with recombinant Sse of M1 GAS (SseM1) and challenged with MGAS5005 (serotype M1, CovS mutant, and Sse of variant complex I), MGAS315 (M3, CovS mutant, and Sse of variant complex I), MGAS2221 (M1, wild-type CovRS, and Sse of variant complex I), and MGAS6180 (M28, wild-type CovRS, and Sse of variant complex II). SseM1 immunization significantly increased survival rates of mice in subcutaneous MGAS5005 and intraperitoneal MGAS6180 challenges and showed consistently higher or longer survival in the other challenges. Immunized mice had smaller skin lesion and higher neutrophil responses in subcutaneous infections and lower GAS burdens in spleen, liver, and kidney in most of the challenge experiments than control mice. SseM1 immunization enhanced proinflammatory responses. These data suggest that Sse immunization has a broad benefit against GAS infections that can vary in extent from strain to strain and that the benefit may be due to the immunization-enhanced proinflammatory responses. In particular, immunization with SseM1 can provide protection against M28 GAS infection even though its Sse and SseM1 have significant variations.
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Affiliation(s)
- Xiaolan Zhang
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Deqin Wei
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yuan Zhao
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Zhaohua Zhong
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yue Wang
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yingli Song
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Minghui Cai
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Wenli Zhang
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Jizi Zhao
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Chunmei Lv
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Hui Zhu
- College of Basic Medical Sciences, Harbin Medical University, Harbin, China
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Tissue Tropism in Streptococcal Infection: Wild-Type M1T1 Group A Streptococcus Is Efficiently Cleared by Neutrophils Using an NADPH Oxidase-Dependent Mechanism in the Lung but Not in the Skin. Infect Immun 2019; 87:IAI.00527-19. [PMID: 31331954 DOI: 10.1128/iai.00527-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 07/14/2019] [Indexed: 11/20/2022] Open
Abstract
Group A Streptococcus (GAS) commonly causes pharyngitis and skin infections. Little is known why streptococcal pharyngitis usually does not lead to pneumonia and why the skin is a favorite niche for GAS. To partially address these questions, the effectiveness of neutrophils in clearing wild-type (wt) M1T1 GAS strain MGAS2221 from the lung and from the skin was examined in murine models of intratracheal pneumonia and subcutaneous infection. Ninety-nine point seven percent of the MGAS2221 inoculum was cleared from the lungs of C57BL/6J mice at 24 h after inoculation, while there was no MGAS2221 clearance from skin infection sites. The bronchial termini had robust neutrophil infiltration, and depletion of neutrophils abolished MGAS2221 clearance from the lung. Phagocyte NADPH oxidase but not myeloperoxidase was required for MGAS2221 clearance. Thus, wt M1T1 GAS can be cleared by neutrophils using an NADPH oxidase-dependent mechanism in the lung. MGAS2221 induced robust neutrophil infiltration at the edge of skin infection sites and throughout infection sites at 24 h and 48 h after inoculation, respectively. Neutrophils within MGAS2221 infection sites had no nuclear staining. Skin infection sites of streptolysin S-deficient MGAS2221 ΔsagA were full of neutrophils with nuclear staining, whereas MGAS2221 ΔsagA infection was not cleared. Gp91phox knockout (KO) and control mice had similar GAS numbers at skin infection sites and similar abilities to select SpeB activity-negative (SpeBA-) variants. These results indicate that phagocyte NADPH oxidase-mediated GAS killing is compromised in the skin. Our findings support a model for GAS skin tropism in which GAS generates an anoxic niche to evade phagocyte NADPH oxidase-mediated clearance.
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Complete Genome Sequence of Hypervirulent Streptococcus pyogenes emm3 Strain 1838. Microbiol Resour Announc 2019; 8:MRA01494-18. [PMID: 30643894 PMCID: PMC6328667 DOI: 10.1128/mra.01494-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/03/2018] [Indexed: 11/20/2022] Open
Abstract
We report the complete genome sequence for Streptococcus pyogenes strain 1838 (type emm3) isolated from a patient with toxic shock syndrome. The strain lacked the speK- and sla-encoding prophage frequently encountered among emm3 strains and possessed an Arg66His mutation in CovR of the 2-component virulence regulatory system CovRS.
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8
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Abstract
Group A Streptococcus (GAS) causes common pharyngitis and skin infections and occasional severe invasive infections. This review describes the recent progress on the pathogenesis of hypervirulent GAS. CovRS mutations are frequent among invasive GAS isolates and lead to hypervirulence. GAS CovRS mutants can be selected in vivo by neutrophils. The role of protease SpeB in source-sink dynamics of wild-type GAS and hypervirulent variants is discussed. Streptolysin S and PAF acetylhydrolase Sse critically and synergistically contribute to the inhibition of neutrophil recruitment by GAS CovS mutants. CovS mutations in emm3 GAS lead to the vascular invasion and enhance systemic GAS dissemination.
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Lei B, Minor D, Feng W, Liu M. Hypervirulent Group A Streptococcus of Genotype emm3 Invades the Vascular System in Pulmonary Infection of Mice. Infect Immun 2018; 86:e00080-18. [PMID: 29610254 PMCID: PMC5964506 DOI: 10.1128/iai.00080-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/22/2018] [Indexed: 11/20/2022] Open
Abstract
Natural mutations of the two-component regulatory system CovRS are frequently associated with invasive group A Streptococcus (GAS) isolates and lead to the enhancement of virulence gene expression, innate immune evasion, systemic dissemination, and virulence. How CovRS mutations enhance systemic dissemination is not well understood. A hypervirulent GAS isolate of the emm3 genotype, MGAS315, was characterized using a mouse model of pulmonary infection to understand systemic dissemination. This strain has a G1370T mutation in the sensor kinase covS gene of CovRS. Intratracheal inoculation of MGAS315 led to the lung infection that displayed extensive Gram staining at the alveolar ducts, alveoli, and peribronchovascular and perivascular interstitium. The correction of the covS mutation did not alter the infection at the alveolar ducts and alveoli but prevented GAS invasion of the peribronchovascular and perivascular interstitium. Furthermore, the covS mutation allowed MGAS315 to disrupt and degrade the smooth muscle and endothelial layers of the blood vessels, directly contributing to systemic dissemination. It is concluded that hypervirulent emm3 GAS covS mutants can invade the perivascular interstitium and directly attack the vascular system for systemic dissemination.
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Affiliation(s)
- Benfang Lei
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Dylan Minor
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Wenchao Feng
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Mengyao Liu
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
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Requirement and Synergistic Contribution of Platelet-Activating Factor Acetylhydrolase Sse and Streptolysin S to Inhibition of Neutrophil Recruitment and Systemic Infection by Hypervirulent emm3 Group A Streptococcus in Subcutaneous Infection of Mice. Infect Immun 2017; 85:IAI.00530-17. [PMID: 28947648 DOI: 10.1128/iai.00530-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 09/18/2017] [Indexed: 01/18/2023] Open
Abstract
Hypervirulent group A streptococcus (GAS) can inhibit neutrophil recruitment and cause systemic infection in a mouse model of skin infection. The purpose of this study was to determine whether platelet-activating factor acetylhydrolase Sse and streptolysin S (SLS) have synergistic contributions to inhibition of neutrophil recruitment and systemic infection in subcutaneous infection of mice by MGAS315, a hypervirulent genotype emm3 GAS strain. Deletion of sse and sagA in MGAS315 synergistically reduced the skin lesion size and GAS burden in the liver and spleen. However, the mutants were persistent at skin sites and had similar growth factors in nonimmune blood. Thus, the low numbers of Δsse ΔsagA mutants in the liver and spleen were likely due to their reduction in the systemic dissemination. Few intact and necrotic neutrophils were detected at MGAS315 infection sites. In contrast, many neutrophils and necrotic cells were present at the edge of Δsse mutant infection sites on day 1 and at the edge of and inside Δsse mutant infection sites on day 2. ΔsagA mutant infection sites had massive numbers of and few intact neutrophils at the edge and center of the infection sites, respectively, on day 1 and were full of intact neutrophils or necrotic cells on day 2. Δsse ΔsagA mutant infection sites had massive numbers of intact neutrophils throughout the whole infection site. These sse and sagA deletion-caused changes in the histological pattern at skin infection sites could be complemented. Thus, the sse and sagA deletions synergistically enhance neutrophil recruitment. These findings indicate that both Sse and SLS are required but that neither is sufficient for inhibition of neutrophil recruitment and systemic infection by hypervirulent GAS.
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Use of a Phosphorylation Site Mutant To Identify Distinct Modes of Gene Repression by the Control of Virulence Regulator (CovR) in Streptococcus pyogenes. J Bacteriol 2017; 199:JB.00835-16. [PMID: 28289082 DOI: 10.1128/jb.00835-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/03/2017] [Indexed: 11/20/2022] Open
Abstract
Control of the virulence regulator/sensor kinase (CovRS) two-component system (TCS) serves as a model for investigating the impact of signaling pathways on the pathogenesis of Gram-positive bacteria. However, the molecular mechanisms by which CovR, an OmpR/PhoB family response regulator, controls virulence gene expression are poorly defined, partly due to the labile nature of its aspartate phosphorylation site. To better understand the regulatory effect of phosphorylated CovR, we generated the phosphorylation site mutant strain 10870-CovR-D53E, which we predicted to have a constitutive CovR phosphorylation phenotype. Interestingly, this strain showed CovR activity only for a subset of the CovR regulon, which allowed for classification of CovR-influenced genes into D53E-regulated and D53E-nonregulated groups. Inspection of the promoter sequences of genes belonging to each group revealed distinct promoter architectures with respect to the location and number of putative CovR-binding sites. Electrophoretic mobility shift analysis demonstrated that recombinant CovR-D53E protein retains its ability to bind promoter DNA from both CovR-D53E-regulated and -nonregulated groups, implying that factors other than mere DNA binding are crucial for gene regulation. In fact, we found that CovR-D53E is incapable of dimerization, a process thought to be critical to OmpR/PhoB family regulator function. Thus, our global analysis of CovR-D53E indicates dimerization-dependent and dimerization-independent modes of CovR-mediated repression, thereby establishing distinct mechanisms by which this critical regulator coordinates virulence gene expression.IMPORTANCEStreptococcus pyogenes causes a wide variety of diseases, ranging from superficial skin and throat infections to life-threatening invasive infections. To establish these various disease manifestations, Streptococcus pyogenes requires tightly coordinated production of its virulence factor repertoire. Here, the response regulator CovR plays a crucial role. As an OmpR/PhoB family member, CovR is activated by phosphorylation on a conserved aspartate residue, leading to protein dimerization and subsequent binding to operator sites. Our transcriptome analysis using the monomeric phosphorylation mimic mutant CovR-D53E broadens this general notion by revealing dimerization-independent repression of a subset of CovR-regulated genes. Combined with promoter analyses, these data suggest distinct mechanisms of CovR transcriptional control, which allow for differential expression of virulence genes in response to environmental cues.
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Vega LA, Valdes KM, Sundar GS, Belew AT, Islam E, Berge J, Curry P, Chen S, El-Sayed NM, Le Breton Y, McIver KS. The Transcriptional Regulator CpsY Is Important for Innate Immune Evasion in Streptococcus pyogenes. Infect Immun 2017; 85:e00925-16. [PMID: 27993974 PMCID: PMC5328483 DOI: 10.1128/iai.00925-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/13/2016] [Indexed: 01/01/2023] Open
Abstract
As an exclusively human pathogen, Streptococcus pyogenes (the group A streptococcus [GAS]) has specifically adapted to evade host innate immunity and survive in multiple tissue niches, including blood. GAS can overcome the metabolic constraints of the blood environment and expresses various immunomodulatory factors necessary for survival and immune cell resistance. Here we present our investigation of one such factor, the predicted LysR family transcriptional regulator CpsY. The encoding gene, cpsY, was initially identified as being required for GAS survival in a transposon-site hybridization (TraSH) screen in whole human blood. CpsY is homologous with transcriptional regulators of Streptococcus mutans (MetR), Streptococcus iniae (CpsY), and Streptococcus agalactiae (MtaR) that regulate methionine transport, amino acid metabolism, resistance to neutrophil-mediated killing, and survival in vivo Our investigation indicated that CpsY is involved in GAS resistance to innate immune cells of its human host. However, GAS CpsY does not manifest the in vitro phenotypes of its homologs in other streptococcal species. GAS CpsY appears to regulate a small set of genes that is markedly different from the regulons of its homologs. The differential expression of these genes depends on the growth medium, and CpsY modestly influences their expression. The GAS CpsY regulon includes known virulence factors (mntE, speB, spd, nga [spn], prtS [SpyCEP], and sse) and cell surface-associated factors of GAS (emm1, mur1.2, sibA [cdhA], and M5005_Spy0500). Intriguingly, the loss of CpsY in GAS does not result in virulence defects in murine models of infection, suggesting that CpsY function in immune evasion is specific to the human host.
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Affiliation(s)
- Luis A Vega
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Kayla M Valdes
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Ganesh S Sundar
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Ashton T Belew
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Emrul Islam
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Jacob Berge
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Patrick Curry
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Steven Chen
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Najib M El-Sayed
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, USA
| | - Yoann Le Breton
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Kevin S McIver
- Department of Cell Biology & Molecular Genetics and Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
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13
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Null Mutations of Group A Streptococcus Orphan Kinase RocA: Selection in Mouse Infection and Comparison with CovS Mutations in Alteration of In Vitro and In Vivo Protease SpeB Expression and Virulence. Infect Immun 2016; 85:IAI.00790-16. [PMID: 27795364 DOI: 10.1128/iai.00790-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 10/17/2016] [Indexed: 12/19/2022] Open
Abstract
Group A Streptococcus (GAS) acquires mutations of the virulence regulator CovRS in human and mouse infections, and these mutations result in the upregulation of virulence genes and the downregulation of the protease SpeB. To identify in vivo mutants with novel phenotypes, GAS isolates from infected mice were screened by enzymatic assays for SpeB and the platelet-activating factor acetylhydrolase Sse, and a new type of variant that had enhanced Sse expression and normal levels of SpeB production was identified (the variants had a phenotype referred to as enhanced Sse activity [SseA+] and normal SpeB activity [SpeBA+]). SseA+ SpeBA+ variants had transcript levels of CovRS-controlled virulence genes comparable to those of a covS mutant but had no covRS mutations. Genome resequencing of an SseA+ SpeBA+ isolate identified a C605A nonsense mutation in orphan kinase gene rocA, and 6 other SseA+ SpeBA+ isolates also had nonsense mutations or small indels in rocA RocA and CovS mutants had similar levels of enhancement of the expression of CovRS-controlled virulence genes at the exponential growth phase; however, mutations of RocA but not mutations of CovS did not result in the downregulation of speB transcription at stationary growth phase or in subcutaneous infection of mice. GAS with RocA and CovS mutations caused greater enhancement of the expression of hasA than spyCEP in mouse skin infection than wild-type GAS did. RocA mutants ranked between wild-type GAS and CovS mutants in skin invasion, inhibition of neutrophil recruitment, and virulence in subcutaneous infection of mice. Thus, GAS RocA mutants can be selected in subcutaneous infections in mice and exhibit gene expression patterns and virulences distinct from those of CovS mutants. The findings provide novel information for understanding GAS fitness mutations in vivo, virulence gene regulation, in vivo gene expression, and virulence.
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Feng W, Liu M, Chen DG, Yiu R, Fang FC, Lei B. Contemporary Pharyngeal and Invasive emm1 and Invasive emm12 Group A Streptococcus Isolates Exhibit Similar In Vivo Selection for CovRS Mutants in Mice. PLoS One 2016; 11:e0162742. [PMID: 27611332 PMCID: PMC5017694 DOI: 10.1371/journal.pone.0162742] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/26/2016] [Indexed: 12/15/2022] Open
Abstract
Group A Streptococcus (GAS) causes diverse infections ranging from common pharyngitis to rare severe invasive infections. Invasive GAS isolates can have natural mutations in the virulence regulator CovRS, which result in enhanced expression of multiple virulence genes, suppressed the expression of the protease SpeB, and increased virulence. It is believed that CovRS mutations arise during human infections with GAS carrying wild-type CovRS and are not transmissible. CovRS mutants of invasive GAS of the emm1 genotype arise readily during experimental infection in mice. It is possible that invasive GAS arises from pharyngeal GAS through rare genetic mutations that confer the capacity of mutated GAS to acquire covRS mutations during infection. The objective of this study was to determine whether contemporary pharyngeal emm1 GAS isolates have a reduced propensity to acquire CovRS mutations in vivo compared with invasive emm1 GAS and whether emm3, emm12, and emm28 GAS acquire CovRS mutants in mouse infection. The propensity of invasive and pharyngeal emm1 and invasive emm3, emm12, and emm28 SpeBA+ isolates to acquire variants with the SpeBA- phenotype was determined during subcutaneous infection of mice. The majority of both invasive and pharyngeal emm1 SpeBA+ isolates and two of three emm12 isolates, but not emm3 and emm28 isolates, were found to acquire SpeBA- variants during skin infection in mice. All analyzed SpeBA- variants of emm1 and emm12 GAS from the mouse infection acquired covRS mutations and produced more platelet-activating factor acetylhydrolase SsE. Thus, contemporary invasive and pharyngeal emm1 GAS isolates and emm12 GAS have a similar capacity to acquire covRS mutations in vivo. The rarity of severe invasive infections caused by GAS does not appear to be attributable to a reduced ability of pharyngeal isolates to acquire CovRS mutations.
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Affiliation(s)
- Wenchao Feng
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
| | - Mengyao Liu
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
| | - Daniel G. Chen
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
| | - Rossana Yiu
- Harborview Medical Center Clinical Microbiology Laboratory and University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Ferric C. Fang
- Harborview Medical Center Clinical Microbiology Laboratory and University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Benfang Lei
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59718, United States of America
- * E-mail:
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A Multi-Serotype Approach Clarifies the Catabolite Control Protein A Regulon in the Major Human Pathogen Group A Streptococcus. Sci Rep 2016; 6:32442. [PMID: 27580596 PMCID: PMC5007534 DOI: 10.1038/srep32442] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/04/2016] [Indexed: 12/20/2022] Open
Abstract
Catabolite control protein A (CcpA) is a highly conserved, master regulator of carbon source utilization in gram-positive bacteria, but the CcpA regulon remains ill-defined. In this study we aimed to clarify the CcpA regulon by determining the impact of CcpA-inactivation on the virulence and transcriptome of three distinct serotypes of the major human pathogen Group A Streptococcus (GAS). CcpA-inactivation significantly decreased GAS virulence in a broad array of animal challenge models consistent with the idea that CcpA is critical to gram-positive bacterial pathogenesis. Via comparative transcriptomics, we established that the GAS CcpA core regulon is enriched for highly conserved CcpA binding motifs (i.e. cre sites). Conversely, strain-specific differences in the CcpA transcriptome seems to consist primarily of affected secondary networks. Refinement of cre site composition via analysis of the core regulon facilitated development of a modified cre consensus that shows promise for improved prediction of CcpA targets in other medically relevant gram-positive pathogens.
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Bachert BA, Choi SJ, LaSala PR, Harper TI, McNitt DH, Boehm DT, Caswell CC, Ciborowski P, Keene DR, Flores AR, Musser JM, Squeglia F, Marasco D, Berisio R, Lukomski S. Unique Footprint in the scl1.3 Locus Affects Adhesion and Biofilm Formation of the Invasive M3-Type Group A Streptococcus. Front Cell Infect Microbiol 2016; 6:90. [PMID: 27630827 PMCID: PMC5005324 DOI: 10.3389/fcimb.2016.00090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/15/2016] [Indexed: 12/04/2022] Open
Abstract
The streptococcal collagen-like proteins 1 and 2 (Scl1 and Scl2) are major surface adhesins that are ubiquitous among group A Streptococcus (GAS). Invasive M3-type strains, however, have evolved two unique conserved features in the scl1 locus: (i) an IS1548 element insertion in the scl1 promoter region and (ii) a nonsense mutation within the scl1 coding sequence. The scl1 transcript is drastically reduced in M3-type GAS, contrasting with a high transcription level of scl1 allele in invasive M1-type GAS. This leads to a lack of Scl1 expression in M3 strains. In contrast, while scl2 transcription and Scl2 production are elevated in M3 strains, M1 GAS lack Scl2 surface expression. M3-type strains were shown to have reduced biofilm formation on inanimate surfaces coated with cellular fibronectin and laminin, and in human skin equivalents. Repair of the nonsense mutation and restoration of Scl1 expression on M3-GAS cells, restores biofilm formation on cellular fibronectin and laminin coatings. Inactivation of scl1 in biofilm-capable M28 and M41 strains results in larger skin lesions in a mouse model, indicating that lack of Scl1 adhesin promotes bacterial spread over localized infection. These studies suggest the uniquely evolved scl1 locus in the M3-type strains, which prevents surface expression of the major Scl1 adhesin, contributed to the emergence of the invasive M3-type strains. Furthermore these studies provide insight into the molecular mechanisms mediating colonization, biofilm formation, and pathogenesis of group A streptococci.
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Affiliation(s)
- Beth A Bachert
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Soo J Choi
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Paul R LaSala
- Department of Pathology, West Virginia University Morgantown, WV, USA
| | - Tiffany I Harper
- Department of Pathology, West Virginia University Morgantown, WV, USA
| | - Dudley H McNitt
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Dylan T Boehm
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Clayton C Caswell
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Pawel Ciborowski
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center Omaha, NE, USA
| | | | - Anthony R Flores
- Section of Infectious Diseases, Department of Pediatrics, Baylor College of Medicine, Texas Children's HospitalHouston, TX, USA; Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute and Hospital SystemHouston, TX, USA
| | - James M Musser
- Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute and Hospital System Houston, TX, USA
| | - Flavia Squeglia
- Institute of Biostructures and Bioimaging, National Research Council Naples, Italy
| | - Daniela Marasco
- Department of Pharmacy, University of Naples Frederico II Naples, Italy
| | - Rita Berisio
- Institute of Biostructures and Bioimaging, National Research Council Naples, Italy
| | - Slawomir Lukomski
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
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The Mga Regulon but Not Deoxyribonuclease Sda1 of Invasive M1T1 Group A Streptococcus Contributes to In Vivo Selection of CovRS Mutations and Resistance to Innate Immune Killing Mechanisms. Infect Immun 2015; 83:4293-303. [PMID: 26283338 DOI: 10.1128/iai.00857-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/11/2015] [Indexed: 11/20/2022] Open
Abstract
Invasive M1T1 group A Streptococcus (GAS) can have a mutation in the regulatory system CovRS, and this mutation can render strains hypervirulent. Interestingly, via mechanisms that are not well understood, the host innate immune system's neutrophils select spontaneous M1T1 GAS CovRS hypervirulent mutants, thereby enhancing the pathogen's ability to evade immune killing. It has been reported that the DNase Sda1 is critical for the resistance of M1T1 strain 5448 to killing in human blood and provides pressure for in vivo selection of CovRS mutations. We reexamined the role of Sda1 in the selection of CovRS mutations and in GAS innate immune evasion. Deletion of sda1 or all DNase genes in M1T1 strain MGAS2221 did not alter emergence of CovRS mutants during murine infection. Deletion of sda1 in strain 5448 resulted in Δsda1 mutants with (5448 Δsda1(M+) strain) and without (5448 Δsda1(M-) strain) M protein production. The 5448 Δsda1(M+) strain accumulated CovRS mutations in vivo and resisted killing in the bloodstream, whereas the 5448 Δsda1(M-) strain lost in vivo selection of CovRS mutations and was sensitive to killing. The deletion of emm and a spontaneous Mga mutation in MGAS2221 reduced and prevented in vivo selection for CovRS mutants, respectively. Thus, in contrast to previous reports, Sda1 is not critical for in vivo selection of invasive M1T1 CovRS mutants and GAS resistance to innate immune killing mechanisms. In contrast, M protein and other Mga-regulated proteins contribute to the in vivo selection of M1T1 GAS CovRS mutants. These findings advance the understanding of the progression of invasive M1T1 GAS infections.
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Miller EW, Danger JL, Ramalinga AB, Horstmann N, Shelburne SA, Sumby P. Regulatory rewiring confers serotype-specific hyper-virulence in the human pathogen group A Streptococcus. Mol Microbiol 2015; 98:473-89. [PMID: 26192205 DOI: 10.1111/mmi.13136] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2015] [Indexed: 12/18/2022]
Abstract
Phenotypic heterogeneity is commonly observed between isolates of a given pathogen. Epidemiological analyses have identified that some serotypes of the group A Streptococcus (GAS) are non-randomly associated with particular disease manifestations. Here, we present evidence that a contributing factor to the association of serotype M3 GAS isolates with severe invasive infections is the presence of a null mutant allele for the orphan kinase RocA. Through use of RNAseq analysis, we identified that the natural rocA mutation present within M3 isolates leads to the enhanced expression of more than a dozen immunomodulatory virulence factors, enhancing phenotypes such as hemolysis and NAD(+) hydrolysis. Consequently, an M3 GAS isolate survived human phagocytic killing at a level 13-fold higher than a rocA complemented derivative, and was significantly more virulent in a murine bacteremia model of infection. Finally, we identified that RocA functions through the CovR/S two-component system as levels of phosphorylated CovR increase in the presence of functional RocA, and RocA has no regulatory activity following covR or covS mutation. Our data are consistent with RocA interfacing with the CovR/S two-component system, and that the absence of this activity in M3 GAS potentiates the severity of invasive infections caused by isolates of this serotype.
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Affiliation(s)
- Eric W Miller
- Department of Microbiology & Immunology, School of Medicine, University of Nevada, Reno, Nevada, USA
| | - Jessica L Danger
- Department of Microbiology & Immunology, School of Medicine, University of Nevada, Reno, Nevada, USA
| | - Anupama B Ramalinga
- Department of Microbiology & Immunology, School of Medicine, University of Nevada, Reno, Nevada, USA
| | - Nicola Horstmann
- Department of Infectious Diseases, MD Anderson Cancer Center, Houston, Texas, USA
| | - Samuel A Shelburne
- Department of Infectious Diseases, MD Anderson Cancer Center, Houston, Texas, USA
| | - Paul Sumby
- Department of Microbiology & Immunology, School of Medicine, University of Nevada, Reno, Nevada, USA
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