1
|
Cullen R, Teçza M, Miclot T, Behan S, Jain M, Avink MK, Cooney JC, Kagawa TF. The 1.7 Å crystal structure of the C5a peptidase from Streptococcus agalactiae (ScpB) reveals an active site competent for catalysis. Proteins 2024; 92:427-431. [PMID: 37921533 DOI: 10.1002/prot.26625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/02/2023] [Accepted: 10/17/2023] [Indexed: 11/04/2023]
Abstract
A 1.7 Å structure is presented for an active form of the virulence factor ScpB, the C5a peptidase from Streptococcus agalactiae. The previously reported structure of the ScpB active site mutant exhibited a large separation (~20 Å) between the catalytic His and Ser residues. Significant differences are observed in the catalytic domain between the current and mutant ScpB structures resulting with a high RMSDCα (4.6 Å). The fold of the active form of ScpB is nearly identical to ScpA (RMSDCα 0.2 Å), the C5a-peptidase from Streptococcus pyogenes. Both ScpA and ScpB have comparable activity against human C5a, indicating neither enzyme require host proteins for C5a-ase activity. These studies are a first step in resolving reported differences in the specificities of these enzymes.
Collapse
Affiliation(s)
- Ruth Cullen
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Malgorzata Teçza
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Tom Miclot
- Lycée Stanislas, Villers-de-Nancy, France
| | - Senan Behan
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Monica Jain
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Marjet Klein Avink
- School of Life Sciences, Engineering and Design, University of Applied Sciences, Saxion, The Netherlands
| | - Jakki C Cooney
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
- Bernal Institute, University of Limerick, Limerick, Ireland
- SSPC, University of Limerick, Limerick, Ireland
| | - Todd F Kagawa
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
- SSPC, University of Limerick, Limerick, Ireland
| |
Collapse
|
2
|
Park HR, Hogan KA, Harris SM, Chames MC, Loch-Caruso R. Group B streptococcus induces cellular senescence in human amnion epithelial cells through a partial interleukin-1-mediated mechanism. Biol Reprod 2024; 110:329-338. [PMID: 37903065 PMCID: PMC10873272 DOI: 10.1093/biolre/ioad149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/25/2023] [Accepted: 10/24/2023] [Indexed: 11/01/2023] Open
Abstract
Group B streptococcus (GBS) infection is a significant public health concern associated with adverse pregnancy complications and increased neonatal mortality and morbidity. However, the mechanisms underlying the impact of GBS on the fetal membrane, the first line of defense against pathogens, are not fully understood. Here, we propose that GBS induces senescence and inflammatory factors (IL-6 and IL-8) in the fetal membrane through interleukin-1 (IL-1). Utilizing the existing transcriptomic data on GBS-exposed human fetal membrane, we showed that GBS affects senescence-related pathways and genes. Next, we treated primary amnion epithelial cells with conditioned medium from the choriodecidual layer of human fetal membrane exposed to GBS (GBS collected choriodecidual [CD] conditioned medium) in the absence or presence of an IL-1 receptor antagonist (IL-1Ra). GBS CD conditioned medium significantly increased β-galactosidase activity, IL-6 and IL-8 release from the amnion epithelial cells. Cotreatment with IL1Ra reduced GBS-induced β-galactosidase activity and IL-6 and IL-8 secretion. Direct treatment with IL-1α or IL-1β confirmed the role of IL-1 signaling in the regulation of senescence in the fetal membrane. We further showed that GBS CD conditioned medium and IL-1 decreased cell proliferation in amnion epithelial cells. In summary, for the first time, we demonstrate GBS-induced senescence in the fetal membrane and present evidence of IL-1 pathway signaling between the choriodecidua and amnion layer of fetal membrane in a paracrine manner. Further studies will be warranted to understand the pathogenesis of adverse pregnancy outcomes associated with GBS infection and develop therapeutic interventions to mitigate these complications.
Collapse
Affiliation(s)
- Hae-Ryung Park
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Kelly A Hogan
- Department of Biochemistry & Molecular Biology, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA
| | - Sean M Harris
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Mark C Chames
- Department of Obstetrics and Gynecology, School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Rita Loch-Caruso
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
3
|
Cai X, Yang S, Peng Y, Tan K, Xu P, Wu Z, Kwan KY, Jian J. Regulation of PhoB on biofilm formation and hemolysin gene hlyA and ciaR of Streptococcus agalactiae. Vet Microbiol 2024; 289:109961. [PMID: 38147806 DOI: 10.1016/j.vetmic.2023.109961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 12/08/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023]
Abstract
PhoB is a response regulator protein that plays a key role in the PhoBR two-component signal transduction system. In this study, we used transcriptome and proteomics techniques to evaluate the detect the gene network regulated by PhoB of Streptococcus agalactiae. The results showed that expression of biofilm formation and virulence-related genes were changed after phoB deficiency. Crystal violet and CLSM assay confirmed that the deletion of the phoB increased the thickness of S. agalactiae biofilm. The results of lacZ reporter and the bacterial one-hybridization method showed that PhoB could directly bind to the promoter regions of hemolysin A and ciaR genes but not to the promoter regions of cylE and hemolysin III. Through the construction of an 18-base pair deoxyribose nucleic acid (DNA) random fragment library and the bacterial one-hybridization system, it was found that the conservative sequence of PhoB binding was TTGGAGAA(G/T). Our research has uncovered the virulence potential of the PhoBR two-component system of S. agalactiae. The findings of this study provide the theoretical foundation for in-depth research on the pathogenic mechanism of S. agalactiae.
Collapse
Affiliation(s)
- Xiaohui Cai
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Shaoyu Yang
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Yinhui Peng
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China; College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, China
| | - Kianann Tan
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Peng Xu
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China
| | - Zaohe Wu
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, China
| | - Kit Yue Kwan
- Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Ocean College, Beibu Gulf University, Qinzhou 535011, China.
| | - Jichang Jian
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, China.
| |
Collapse
|
4
|
Zheng Q, Liu Z, Sun C, Dong J, Zhang H, Ke X, Gao F, Lu M. Molecular characterization, expression and functional analysis of TAK1, TAB1 and TAB2 in Nile tilapia (Oreochromis niloticus). Fish Shellfish Immunol 2024; 145:109359. [PMID: 38184182 DOI: 10.1016/j.fsi.2024.109359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/27/2023] [Accepted: 01/04/2024] [Indexed: 01/08/2024]
Abstract
The MAPK pathway is the common intersection of signal transduction pathways such as inflammation, differentiation and proliferation and plays an important role in the process of antiviral immunity. Streptococcus agalactiae will have a great impact on tilapia aquaculture, so it is necessary to study the immune response mechanism of tilapia to S. agalactiae. In this study, we isolated the cDNA sequences of TAK1, TAB1 and TAB2 from Nile tilapia (Oreochromis niloticus). The TAK1 gene was 3492 bp in length, contained an open reading frame (ORF) of 1809 bp and encoded a polypeptide of 602 amino acids. The cDNA sequence of the TAB1 gene was 4001 bp, and its ORF was 1491 bp, which encoded 497 amino acids. The cDNA sequence of the TAB2 gene was 4792 bp, and its ORF was 2217 bp, encoding 738 amino acids. TAK1 has an S_TKc domain and a coiled coil structure; the TAB1 protein structure contains a PP2C_SIG domain and a conserved PYVDXA/TXF sequence model; and TAB2 contains a CUE domain, a coiled coil domain and a Znf_RBZ domain. Homology analysis showed that TAK1 and TAB1 had the highest homology with Neolamprologus brichardi, and TAB2 had the highest homology with Simochromis diagramma (98.28 %). In the phylogenetic tree, TAK1, TAB1 and TAB2 formed a large branch with other scleractinian fishes. The tissue expression analysis showed that the expression of TAK1, TAB1 and TAB2 was highest in the muscle. The expression of TAK1, TAB1 and TAB2 was significantly induced in most of the tested tissues after stimulation with LPS, Poly I:C and S. agalactiae. The subcellular localization results showed that TAK1 was located in the cytoplasm, and TAB1 and TAB2 had certain distributions in the cytoplasm and nucleus. Coimmunoprecipitation (Co-IP) results showed that TRAF6 did not interact with the TAK1 protein but interacted with TAB2, while TAB1 did not interact with P38γ but interacted with TAK1. There was also an interaction between TAK1 and TAB2.
Collapse
Affiliation(s)
- Qiuyue Zheng
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, 201306, China
| | - Zhigang Liu
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China
| | - Chengfei Sun
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China
| | - Junjian Dong
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China
| | - Hetong Zhang
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China
| | - Xiaoli Ke
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China.
| | - Fengying Gao
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China.
| | - Maixin Lu
- Pearl River Fisheries Research Institute, Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation, Ministry of Agriculture, Chinese Academy of Fishery Science, Guangzhou, 510380, China
| |
Collapse
|
5
|
Abdel Rahman AN, Amer SA, Behairy A, Younis EM, Abdelwarith AA, Osman A, Moustafa AA, Davies SJ, Ibrahim RE. Using Azadirachta indica protein hydrolysate as a plant protein in Nile tilapia (Oreochromis niloticus) diet: Effects on the growth, economic efficiency, antioxidant-immune response and resistance to Streptococcus agalactiae. J Anim Physiol Anim Nutr (Berl) 2023; 107:1502-1516. [PMID: 37431590 DOI: 10.1111/jpn.13857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/12/2023]
Abstract
A feeding trial for 90 days was conducted on Nile tilapia (Oreochromis niloticus) (average weight: 25.50 ± 0.05 g) to evaluate the effect of dietary inclusion of Azadirachta indica seed protein hydrolysate (AIPH). The evaluation included the impact on the growth metrics, economic efficiency, antioxidant potential, hemato-biochemical indices, immune response, and histological architectures. A total of 250 fish were randomly distributed in five treatments (n = 50) and received diets included with five levels of AIPH (%): 0 (control diet, AIPH0), 2 (AIPH2), 4 (AIPH4), 6 (AIPH6) or 8 (AIPH8), where AIPH partially replace fish meal by 0, 8.7%, 17.4%, 26.1%, and 34.8%, respectively. After the feeding trial, a pathogenic bacterium (Streptococcus agalactiae, 1.5 × 108 CFU/mL) was intraperitoneally injected into the fish and the survival rate was recorded. The results elucidated that AIPH-included diets significantly (p < 0.05) enhanced the growth indices (final body weight, total feed intake, total body weight gain, and specific growth rate) and intestinal morpho-metrics (villous width, length, muscular coat thickness, and goblet cells count) in comparison to the control diet, with the AIPH8 diet recording the highest values. Dietary AIPH inclusion significantly improved (p < 0.05) the economic efficacy indicated by reduced feed cost/kg gain and increased performance index. The fish fed on the AIPH diets had noticeably significantly higher (p < 0.05) protein profile variables (total proteins and globulin) and antioxidant capabilities (superoxide dismutase and total antioxidant capacity) than the AIPH0 group. The dietary inclusion of AIPH significantly (p < 0.05) boosted the haematological parameters (haemoglobin, packed cell volume %, and counts of red blood cells and white blood cells) and immune indices (serum bactericidal activity %, antiprotease activity, and immunoglobulin M level) in a concentration-dependent manner. The blood glucose and malondialdehyde levels were significantly (p < 0.05) lowered by dietary AIPH (2%-8%). The albumin level and hepatorenal functioning parameters (aspartate aminotransferase, alanine aminotransferase, and creatinine) were not significantly (p > 0.05) altered by AIPH diets. Additionally, AIPH diets did not adversely alter the histology of the hepatic, renal or splenic tissues with moderately activated melano-macrophage centres. The mortality rate among S. agalactiae-infected fish declined as dietary AIPH levels rose, where the highest survival rate (86.67%) was found in the AIPH8 group (p < 0.05). Based on the broken line regression model, our study suggests using dietary AIPH at the optimal level of 6%. Overall, dietary AIPH inclusion enhanced the growth rate, economic efficiency, health status, and resistance of Nile tilapia to the S. agalactiae challenge. These beneficial impacts can help the aquaculture sector to be more sustainable.
Collapse
Affiliation(s)
- Afaf N Abdel Rahman
- Department of Aquatic Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Sharkia, Egypt
| | - Shimaa A Amer
- Department of Nutrition and Clinical Nutrition, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Sharkia, Egypt
| | - Amany Behairy
- Department of Physiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Sharkia, Egypt
| | - Elsayed M Younis
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | | | - Ali Osman
- Biochemistry Department, Faculty of Agriculture, Zagazig University, Zagazig, Sharkia, Egypt
| | - Amr A Moustafa
- Department of Biochemistry, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Simon J Davies
- Aquaculture Nutrition Research Unit ANRU, Carna Research Station, Ryan Institute, College of Science and Engineering, University of Galway, Galway, Ireland
| | - Rowida E Ibrahim
- Department of Aquatic Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Sharkia, Egypt
| |
Collapse
|
6
|
Spencer BL, Job AM, Robertson CM, Hameed ZA, Serchejian C, Wiafe-Kwakye CS, Mendonça JC, Apolonio MA, Nagao PE, Neely MN, Korotkova N, Korotkov KV, Patras KA, Doran KS. Heterogeneity of the group B streptococcal type VII secretion system and influence on colonization of the female genital tract. Mol Microbiol 2023; 120:258-275. [PMID: 37357823 PMCID: PMC10527989 DOI: 10.1111/mmi.15115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Type VIIb secretion systems (T7SSb) in Gram-positive bacteria facilitate physiology, interbacterial competition, and/or virulence via EssC ATPase-driven secretion of small ɑ-helical proteins and toxins. Recently, we characterized T7SSb in group B Streptococcus (GBS), a leading cause of infection in newborns and immunocompromised adults. GBS T7SS comprises four subtypes based on variation in the C-terminus of EssC and the repertoire of downstream effectors; however, the intraspecies diversity of GBS T7SS and impact on GBS-host interactions remains unknown. Bioinformatic analysis indicates that GBS T7SS loci encode subtype-specific putative effectors, which have low interspecies and inter-subtype homology but contain similar domains/motifs and therefore may serve similar functions. We further identify orphaned GBS WXG100 proteins. Functionally, we show that GBS T7SS subtype I and III strains secrete EsxA in vitro and that in subtype I strain CJB111, esxA1 appears to be differentially transcribed from the T7SS operon. Furthermore, we observe subtype-specific effects of GBS T7SS on host colonization, as CJB111 subtype I but not CNCTC 10/84 subtype III T7SS promotes GBS vaginal colonization. Finally, we observe that T7SS subtypes I and II are the predominant subtypes in clinical GBS isolates. This study highlights the potential impact of T7SS heterogeneity on host-GBS interactions.
Collapse
Affiliation(s)
- Brady L. Spencer
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Alyx M. Job
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| | - Clare M. Robertson
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Zainab A. Hameed
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Camille Serchejian
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | | | - Jéssica C. Mendonça
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Morgan A. Apolonio
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
- National Summer Undergraduate Research Program, University of Arizona, Tucson, AZ, USA
| | - Prescilla E. Nagao
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Melody N. Neely
- University of Maine, Molecular & Biomedical Sciences, Orono, ME, USA
| | - Natalia Korotkova
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Konstantin V. Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - Kathryn A. Patras
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Alkek Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX, USA
| | - Kelly S. Doran
- University of Colorado-Anschutz, Department of Immunology and Microbiology, Aurora, CO, USA
| |
Collapse
|
7
|
Briaud P, Gautier T, Rong V, Mereghetti L, Lanotte P, Hiron A. The Streptococcus agalactiae Exonuclease ExoVII Is Required for Resistance to Exogenous DNA-Damaging Agents. J Bacteriol 2023; 205:e0002423. [PMID: 37162366 PMCID: PMC10294681 DOI: 10.1128/jb.00024-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/27/2023] [Indexed: 05/11/2023] Open
Abstract
Streptococcus agalactiae is a human pathogen responsible for severe invasive infections in newborns. In this bacterium, XseB, a part of the ExoVII exonuclease, was shown to be specifically more abundant in the hypervirulent ST-17 strains. In Escherichia coli, ExoVII is associated either with mismatch repair or with recombinational DNA repair and is redundant with other exonucleases. In this study, the biological role of S. agalactiae ExoVII was examined. The ΔexoVII mutant strain was subjected to different DNA-damaging agents, as well as a large set of mutants impaired either in the mismatch repair pathway or in processes of recombinational DNA repair. Our results clarified the role of this protein in Gram-positive bacteria as we showed that ExoVII is not significantly involved in mismatch repair but is involved in bacterial recovery after exposure to exogenous DNA-damaging agents such as ciprofloxacin, UV irradiation, or hydrogen peroxide. We found that ExoVII is more particularly important for resistance to ciprofloxacin, likely as part of the RecF DNA repair pathway. Depending on the tested agent, ExoVII appeared to be fully redundant or nonredundant with another exonuclease, RecJ. The importance of each exonuclease, ExoVII or RecJ, in the process of DNA repair is thus dependent on the considered DNA lesion. IMPORTANCE This study examined the role of the ExoVII exonuclease of Streptococcus agalactiae within the different DNA repair processes. Our results concluded that ExoVII is involved in bacterial recovery after exposure to different exogenous DNA-damaging agents but not in the mismatch repair pathway. We found that ExoVII is particularly important for resistance to ciprofloxacin, likely as part of the RecF DNA repair pathway.
Collapse
Affiliation(s)
- P. Briaud
- Université de Tours, INRAE, ISP, Tours, France
| | - T. Gautier
- Université de Tours, INRAE, ISP, Tours, France
| | - V. Rong
- Université de Tours, INRAE, ISP, Tours, France
| | - L. Mereghetti
- Université de Tours, INRAE, ISP, Tours, France
- CHRU de Tours, Service de Bactériologie-Virologie-Hygiène, Tours, France
| | - P. Lanotte
- Université de Tours, INRAE, ISP, Tours, France
- CHRU de Tours, Service de Bactériologie-Virologie-Hygiène, Tours, France
| | - A. Hiron
- Université de Tours, INRAE, ISP, Tours, France
| |
Collapse
|
8
|
Kuperwaser F, Avital G, Vaz MJ, Noble KN, Dammann AN, Randis TM, Aronoff DM, Ratner AJ, Yanai I. Host inflammatory dynamics reveal placental immune modulation by Group B Streptococcus during pregnancy. Mol Syst Biol 2023; 19:e11021. [PMID: 36744393 PMCID: PMC9996236 DOI: 10.15252/msb.202211021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 02/07/2023] Open
Abstract
Group B Streptococcus (GBS) is a pathobiont that can ascend to the placenta and cause adverse pregnancy outcomes, in part through production of the toxin β-hemolysin/cytolysin (β-h/c). Innate immune cells have been implicated in the response to GBS infection, but the impact of β-h/c on their response is poorly defined. We show that GBS modulates innate immune cell states by subversion of host inflammation through β-h/c, allowing worse outcomes. We used an ascending mouse model of GBS infection to measure placental cell state changes over time following infection with a β-h/c-deficient and isogenic wild type GBS strain. Transcriptomic analysis suggests that β-h/c-producing GBS elicit a worse phenotype through suppression of host inflammatory signaling in placental macrophages and neutrophils, and comparison of human placental macrophages infected with the same strains recapitulates these results. Our findings have implications for identification of new targets in GBS disease to support host defense against pathogenic challenge.
Collapse
Affiliation(s)
- Felicia Kuperwaser
- Institute for Computational MedicineNYU Grossman School of MedicineNew YorkNYUSA
| | - Gal Avital
- Institute for Computational MedicineNYU Grossman School of MedicineNew YorkNYUSA
| | - Michelle J Vaz
- Department of PediatricsNYU Grossman School of MedicineNew YorkNYUSA
| | - Kristen N Noble
- Division of Neonatology, Department of PediatricsVanderbilt University Medical CenterNashvilleTNUSA
| | - Allison N Dammann
- Renaissance School of Medicine at Stony Brook UniversityStony BrookNYUSA
| | - Tara M Randis
- Departments of Pediatrics and Molecular Medicine, Morsani School of MedicineUniversity of South FloridaFLTampaUSA
| | | | - Adam J Ratner
- Department of PediatricsNYU Grossman School of MedicineNew YorkNYUSA
- Department of MicrobiologyNYU Grossman School of MedicineNew YorkNYUSA
| | - Itai Yanai
- Institute for Computational MedicineNYU Grossman School of MedicineNew YorkNYUSA
- Department of Biochemistry and Molecular PharmacologyNYU Grossman School of MedicineNew YorkNYUSA
| |
Collapse
|
9
|
Roux AE, Robert S, Bastat M, Rosinski-Chupin I, Rong V, Holbert S, Mereghetti L, Camiade E. The Role of Regulator Catabolite Control Protein A (CcpA) in Streptococcus agalactiae Physiology and Stress Response. Microbiol Spectr 2022; 10:e0208022. [PMID: 36264242 PMCID: PMC9784791 DOI: 10.1128/spectrum.02080-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/21/2022] [Indexed: 01/06/2023] Open
Abstract
Streptococcus agalactiae is a leading cause of infections in neonates. This opportunistic pathogen colonizes the vagina, where it has to cope with acidic pH and hydrogen peroxide produced by lactobacilli. Thus, in the host, this bacterium possesses numerous adaptation mechanisms in which the pleiotropic regulators play a major role. The transcriptional regulator CcpA (catabolite control protein A) has previously been shown to be the major regulator involved in carbon catabolite repression in Gram-positive bacteria but is also involved in other functions. By transcriptomic analysis, we characterized the CcpA-dependent gene regulation in S. agalactiae. Approximately 13.5% of the genome of S. agalactiae depends on CcpA for regulation and comprises genes involved in sugar uptake and fermentation, confirming the role of CcpA in carbon metabolism. We confirmed by electrophoretic mobility shift assays (EMSAs) that the DNA binding site called cis-acting catabolite responsive element (cre) determined for other streptococci was effective in S. agalactiae. We also showed that CcpA is of capital importance for survival under acidic and oxidative stresses and is implicated in macrophage survival by regulating several genes putatively or already described as involved in stress response. Among them, we focused our study on SAK_1689, which codes a putative UspA protein. We demonstrated that SAK_1689, highly downregulated by CcpA, is overexpressed under oxidative stress conditions, this overexpression being harmful for the bacterium in a ΔccpA mutant. IMPORTANCE Streptococcus agalactiae is a major cause of disease burden leading to morbidity and mortality in neonates worldwide. Deciphering its adaptation mechanisms is essential to understand how this bacterium manages to colonize its host. Here, we determined the regulon of the pleiotropic regulator CcpA in S. agalactiae. Our findings reveal that CcpA is not only involved in carbon catabolite repression, but is also important for acidic and oxidative stress resistance and survival in macrophages.
Collapse
Affiliation(s)
| | | | | | - Isabelle Rosinski-Chupin
- Unité Écologie et Évolution de la Résistance aux Antibiotiques, CNRS UMR3525, Institut Pasteur, Paris, France
| | | | | | - Laurent Mereghetti
- ISP, Université de Tours, INRAE, Tours, France
- CHRU Tours, Service de Bactériologie-Virologie-Hygiène, Tours, France
| | | |
Collapse
|
10
|
Ma F, Yang S, Zhou M, Lu Y, Deng B, Zhang J, Fan H, Wang G. NADPH oxidase-derived reactive oxygen species production activates the ERK1/2 pathway in neutrophil extracellular traps formation by Streptococcus agalactiae isolated from clinical mastitis bovine. Vet Microbiol 2022; 268:109427. [PMID: 35405476 DOI: 10.1016/j.vetmic.2022.109427] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 03/08/2022] [Accepted: 04/01/2022] [Indexed: 11/29/2022]
Abstract
Streptococcus agalactiae (S. agalactiae) continues to be challenging for milk quality in some countries and leads to huge economic losses. A large number of neutrophils are recruited into inflammatory foci when S. agalactiae infection occurs, and most studies have focused on the interaction between neutrophil extracellular traps (NETs) and this bacterium in the context of human pathogenicity. However, there is little information on the NET formation mechanism induced by S. agalactiae in the context of bovine mastitis. Here, neutrophils isolated from BALB/c mice were infected with S. agalactiae SAG-FX17, and NET formation was evaluated. SAG-FX17 could induce NADPH oxidase-derived reactive oxygen species (NOX-ROS)-dependent NET formation, and 21.8% of bacteria could be eliminated by NETs via NET DNA and associated proteins. SAG-FX17 could induce the phosphorylation of p38 MAPK, ERK1/2 MAPK, and JNK/SAPK in neutrophils. However, only ERK1/2 MAPK was shown to play an important role in SAG-FX17-induced NET formation. Importantly, NOX-ROS production occurs upstream of ERK1/2 MAPK activation and then induces NET release. ERK1/2 MAPK phosphorylation can, in turn, enhance NOX-ROS generation, which further contributes to NET release and bacterial elimination. This study provides evidence of the molecular mechanism underlying serotype Ia S. agalactiae SAG-FX17-induced NET formation and the interaction between bacteria and NETs, and these findings will increase our knowledge about bacterial mastitis in dairy cattle and contribute to the prevention and clinical treatment of bovine mastitis.
Collapse
Affiliation(s)
- Fang Ma
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China
| | - Shifang Yang
- College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, China
| | - Mingxu Zhou
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Yu Lu
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Bihua Deng
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Jinqiu Zhang
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Hongjie Fan
- College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, China
| | - Guangyu Wang
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, Jiangsu 210023, China.
| |
Collapse
|
11
|
Burcham LR, Bath JR, Werlang CA, Lyon LM, Liu N, Evans C, Ribbeck K, Doran KS. Role of MUC5B during Group B Streptococcal Vaginal Colonization. mBio 2022; 13:e0003922. [PMID: 35323039 PMCID: PMC9040740 DOI: 10.1128/mbio.00039-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/07/2022] [Indexed: 12/27/2022] Open
Abstract
The female reproductive tract (FRT) is a complex environment, rich in mucin glycoproteins that form a dense network on the surface of the underlying epithelia. Group B Streptococcus (GBS) asymptomatically colonizes 25-30% of healthy women, but during pregnancy can cause ascending infection in utero or be transmitted to the newborn during birth to cause invasive disease. Though the cervicovaginal mucosa is a natural site for GBS colonization, the specific interactions between GBS and mucins remain unknown. Here we demonstrate for the first time that MUC5B interacts directly with GBS and promotes barrier function by inhibiting both bacterial attachment to human epithelial cells and ascension from the vagina to the uterus in a murine model of GBS colonization. RNA sequencing analysis of GBS exposed to MUC5B identified 128 differentially expressed GBS genes, including upregulation of the pilus island-2b (PI-2b) locus. We subsequently show that PI-2b is important for GBS attachment to reproductive cells, binding to immobilized mucins, and vaginal colonization in vivo. Our results suggest that while MUC5B plays an important role in host defense, GBS upregulates pili in response to mucins to help promote persistence within the vaginal tract, illustrating the dynamic interplay between pathogen and host. IMPORTANCE Mucin glycoproteins are a major component that contributes to the complexity of the female reproductive tract (FRT). Group B Streptococcus (GBS) is present in the FRT of 25-30% of healthy women, but during pregnancy can ascend to the uterus to cause preterm birth and fetal infection in utero. Here we show that a prominent mucin found in the FRT, MUC5B, promotes host defense by inhibiting GBS interaction with epithelial cells found in the FRT and ascension from the vagina to the uterus in vivo. In response to MUC5B, GBS induces the expression of surface expressed pili, which in turn contributes to GBS persistence within the vaginal lumen. These observations highlight the importance and complexity of GBS-mucin interactions that warrant further investigation.
Collapse
Affiliation(s)
- Lindsey R. Burcham
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Jade R. Bath
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Caroline A. Werlang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Laurie M. Lyon
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Naoko Liu
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Christopher Evans
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Katharina Ribbeck
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| |
Collapse
|
12
|
Shahi I, Llaneras CN, Perelman SS, Torres VJ, Ratner AJ. Genome-Wide CRISPR-Cas9 Screen Does Not Identify Host Factors Modulating Streptococcus agalactiae β-Hemolysin/Cytolysin-Induced Cell Death. Microbiol Spectr 2022; 10:e0218621. [PMID: 35196804 PMCID: PMC8865549 DOI: 10.1128/spectrum.02186-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/07/2022] [Indexed: 11/20/2022] Open
Abstract
Pore-forming toxins (PFTs) are commonly produced by pathogenic bacteria, and understanding them is key to the development of virulence-targeted therapies. Streptococcus agalactiae, or group B Streptococcus (GBS), produces several factors that enhance its pathogenicity, including the PFT β-hemolysin/cytolysin (βhc). Little is understood about the cellular factors involved in βhc pore formation. We conducted a whole-genome CRISPR-Cas9 forward genetic screen to identify host genes that might contribute to βhc pore formation and cell death. While the screen identified the established receptor, CD59, in control experiments using the toxin intermedilysin (ILY), no clear candidate genes were identified that were required for βhc-mediated lethality. Of the top targets from the screen, two genes involved in membrane remodeling and repair represented candidates that might modulate the kinetics of βhc-induced cell death. Upon attempted validation of the results using monoclonal cell lines with targeted disruption of these genes, no effect on βhc-mediated cell lysis was observed. The CRISPR-Cas9 screen results are consistent with the hypothesis that βhc does not require a single nonessential host factor to mediate target cell death. IMPORTANCE CRISPR-Cas9 forward genetic screens have been used to identify host cell targets required by bacterial toxins. They have been used successfully to both verify known targets and elucidate novel host factors required by toxins. Here, we show that this approach fails to identify host factors required for cell death due to βhc, a toxin required for GBS virulence. These data suggest that βhc may not require a host cell receptor for toxin function or may require a host receptor that is an essential gene and would not be identified using this screening strategy.
Collapse
Affiliation(s)
- Ifrah Shahi
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Cristina N. Llaneras
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Sofya S. Perelman
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Victor J. Torres
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
| | - Adam J. Ratner
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
- Antimicrobial-Resistant Pathogens Program, New York University Grossman School of Medicine, New York, New York, USA
- Department of Pediatrics, New York University Grossman School of Medicine, New York, New York, USA
| |
Collapse
|
13
|
Joyce LR, Manzer HS, da C. Mendonça J, Villarreal R, Nagao PE, Doran KS, Palmer KL, Guan Z. Identification of a novel cationic glycolipid in Streptococcus agalactiae that contributes to brain entry and meningitis. PLoS Biol 2022; 20:e3001555. [PMID: 35180210 PMCID: PMC8893666 DOI: 10.1371/journal.pbio.3001555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 03/03/2022] [Accepted: 01/26/2022] [Indexed: 12/17/2022] Open
Abstract
Bacterial membrane lipids are critical for membrane bilayer formation, cell division, protein localization, stress responses, and pathogenesis. Despite their critical roles, membrane lipids have not been fully elucidated for many pathogens. Here, we report the discovery of a novel cationic glycolipid, lysyl-glucosyl-diacylglycerol (Lys-Glc-DAG), which is synthesized in high abundance by the bacterium Streptococcus agalactiae (Group B Streptococcus, GBS). To our knowledge, Lys-Glc-DAG is more positively charged than any other known lipids. Lys-Glc-DAG carries 2 positive net charges per molecule, distinct from the widely described lysylated phospholipid lysyl-phosphatidylglycerol (Lys-PG) that carries one positive net charge due to the presence of a negatively charged phosphate moiety. We use normal phase liquid chromatography (NPLC) coupled with electrospray ionization (ESI) high-resolution tandem mass spectrometry (HRMS/MS) and genetic approaches to determine that Lys-Glc-DAG is synthesized by the enzyme MprF in GBS, which covalently modifies the neutral glycolipid Glc-DAG with the cationic amino acid lysine. GBS is a leading cause of neonatal meningitis, which requires traversal of the endothelial blood–brain barrier (BBB). We demonstrate that GBS strains lacking mprF exhibit a significant decrease in the ability to invade BBB endothelial cells. Further, mice challenged with a GBSΔmprF mutant developed bacteremia comparably to wild-type (WT) infected mice yet had less recovered bacteria from brain tissue and a lower incidence of meningitis. Thus, our data suggest that Lys-Glc-DAG may contribute to bacterial uptake into host cells and disease progression. Importantly, our discovery provides a platform for further study of cationic lipids at the host–pathogen interface. Bacterial membrane lipids are critical for membrane bilayer formation, cell division, protein localization, stress responses, and pathogenesis. This study shows that the enzyme MprF in Streptococcus agalactiae synthesizes a novel cationic lipid, Lysyl-Glucosyl-Diacylglycerol, which aids meningitis progression in vivo.
Collapse
Affiliation(s)
- Luke R. Joyce
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, United States of America
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Haider S. Manzer
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Jéssica da C. Mendonça
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ricardo Villarreal
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Prescilla E. Nagao
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- * E-mail: (KSD); (KLP); (ZG)
| | - Kelli L. Palmer
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, United States of America
- * E-mail: (KSD); (KLP); (ZG)
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail: (KSD); (KLP); (ZG)
| |
Collapse
|
14
|
Spencer BL, Tak U, Mendonça JC, Nagao PE, Niederweis M, Doran KS. A type VII secretion system in Group B Streptococcus mediates cytotoxicity and virulence. PLoS Pathog 2021; 17:e1010121. [PMID: 34871327 PMCID: PMC8675928 DOI: 10.1371/journal.ppat.1010121] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/16/2021] [Accepted: 11/16/2021] [Indexed: 12/20/2022] Open
Abstract
Type VII secretion systems (T7SS) have been identified in Actinobacteria and Firmicutes and have been shown to secrete effector proteins with functions in virulence, host toxicity, and/or interbacterial killing in a few genera. Bioinformatic analysis indicates that isolates of Group B Streptococcus (GBS) encode at least four distinct subtypes of T7SS machinery, three of which encode adjacent putative T7SS effectors with WXG and LXG motifs. However, the function of T7SS in GBS pathogenesis is unknown. Here we assessed the role of the most abundant GBS T7SS subtype during GBS pathogenesis. In a murine model of hematogenous meningitis, mice infected with GBS lacking a functional T7SS or lacking the secreted WXG100 effector EsxA exhibited less mortality, lower bacterial burdens in tissues, and decreased inflammation in the brain compared to mice infected with the parental GBS strain. We further showed that this T7SS induces cytotoxicity in brain endothelium and that EsxA contributes to these cytotoxicity phenotypes in a WXG motif-dependent manner. Finally, we determined that EsxA is a pore-forming protein, thus demonstrating the first role for a non-mycobacterial EsxA homolog in pore formation. This work reveals the importance of a T7SS in host–GBS interactions and has implications for T7SS effector function in other Gram-positive bacteria. Group B Streptococcus (GBS) is an important human pathogen that is a leading cause of invasive disease in newborns and certain adult populations, including pregnant women, the elderly, and those with diabetes. During pregnancy, asymptomatically colonizing GBS in the female genital tract can be transmitted to the fetus or newborn and can result in neonatal meningitis upon GBS disruption of the blood-brain barrier (BBB). GBS encodes a type VII secretion system (T7SS), which may allow export of proteins and/or toxins that promote BBB disruption; however, the GBS T7SS has not been studied. Here we show that GBS encodes four types of T7SSs and that the most prevalent subtype is important for GBS meningitis progression, possibly by inducing inflammation and cell death in the brain. We also show that a secreted T7SS effector protein, EsxA, contributes to GBS pathogenesis and can form pores in lipid membranes. This is the first demonstration of EsxA-mediated pore-formation in Gram-positive bacteria.
Collapse
Affiliation(s)
- Brady L. Spencer
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
| | - Uday Tak
- University of Alabama at Birmingham, Department of Microbiology, Birmingham, Alabama, United States of America
| | - Jéssica C. Mendonça
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Prescilla E. Nagao
- Rio de Janeiro State University, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro, RJ, Brazil
| | - Michael Niederweis
- University of Alabama at Birmingham, Department of Microbiology, Birmingham, Alabama, United States of America
| | - Kelly S. Doran
- University of Colorado Anschutz Medical Campus, Department of Immunology and Microbiology, Aurora, Colorado, United States of America
- * E-mail:
| |
Collapse
|
15
|
Zhang Z, Niu J, Li Q, Huang Y, Jiang B, Wu Y, Huang Y, Jian J. HMG20A from Nile tilapia (Oreochromis niloticus) involved in the immune response to bacterial infection. Fish Shellfish Immunol 2021; 119:499-507. [PMID: 34687883 DOI: 10.1016/j.fsi.2021.10.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
High-mobility group 20 A (HMG20A) has important biological functions, such as inhibiting the differentiation of red blood cells and nerve cells, promoting the proliferation and metastasis of cancer cells, and regulating inflammatory reaction. However, the role of HMG20A in the response to bacterial infection in the economic fish Nile tilapia (Oreochromis niloticus) remains unclear. In this study, a HMG20A homolog was successfully identified and characterized from Nile tilapia (On-HMG20A), and its expression model and biological effects on bacterial infection were analyzed. The open reading frame (ORF) of On-HMG20A was 876 bp in length, which encoded 291 amino acids and possessed a HMG domain (High mobility group domains) and coiled coil region. Results of the expression model showed that On-HMG20A was widely distributed in immune-related tissues of healthy tilapia and upregulated in a time-dependent manner after being challenged by Streptococcus agalactiae. Meanwhile, knocking down the expression of On-HMG20A can reduce the inflammatory response of tilapia and the degree of tissue damage caused by S. agalactiae. Moreover, knocking down the expression of On-HMG20A can reduce the bacterial load of tilapia tissues after being challenged by S. agalactiae and improve the survival rate. Collectively, these results showed that On-HMG20A may be related to the immune response of Nile tilapia against bacterial infection.
Collapse
Affiliation(s)
- Zhiqiang Zhang
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China
| | - Jinzhong Niu
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China
| | - Qi Li
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China
| | - Yongxiong Huang
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China
| | - Baijian Jiang
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China
| | - Yiqin Wu
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China
| | - Yu Huang
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, China.
| | - Jichang Jian
- College of Fishery, Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animal, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, China
| |
Collapse
|
16
|
Matsui H, Uchiyama J, Ogata M, Nasukawa T, Takemura-Uchiyama I, Kato SI, Murakami H, Higashide M, Hanaki H. Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests. Microbiol Spectr 2021; 9:e0007721. [PMID: 34378963 PMCID: PMC8552716 DOI: 10.1128/spectrum.00077-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/09/2021] [Indexed: 12/17/2022] Open
Abstract
Group B Streptococcus (GBS) causes serious neonatal infection via vertical transmission. The prenatal GBS screening test is performed at the late stage of pregnancy to avoid risks of infection. In this test, enrichment culture is performed, followed by GBS identification. Selective medium is used for the enrichment; however, Enterococcus faecalis, which is a potential contaminant in swab samples, can interfere with the growth of GBS. Such bacterial contamination can lead to false-negative results. Endolysin, a bacteriophage-derived enzyme, degrades peptidoglycan in the bacterial cell wall; it is a promising antimicrobial agent for selectively eliminating specific bacterial genera/species. In this study, we used the recombinant endolysin EG-LYS, which is specific to E. faecalis; the endolysin potentially enriched GBS in the selective culture. First, in the false-negative model (coculture of GBS and E. faecalis, which disabled GBS detection in the subsequent GBS identification test), EG-LYS treatment at 0.1 mg/ml improved GBS detection. Next, we used 548 vaginal swabs to test the efficacy of EG-LYS treatment in improving GBS detection. EG-LYS treatment (0.1 mg/ml) increased the GBS-positive ratio to 17.9%, compared to 15.7% in the control (phosphate-buffered saline [PBS] treatment). In addition, there were an increased number of GBS colonies under EG-LYS treatment in some samples. The results were supported by the microbiota analysis of the enriched cultures. In conclusion, EG-LYS treatment of the enrichment culture potentially improves the accuracy of the prenatal GBS screening test. IMPORTANCE Endolysin is a bacteriophage-derived enzyme that degrades the peptidoglycan in the cell wall of host bacteria; it could be used as an antimicrobial agent for selectively eliminating specific bacterial genera/species. Group B Streptococcus (GBS) causes neonatal infection via vertical transmission; prenatal GBS screening test, in which enrichment culture is followed by bacterial identification, is used to detect the presence of GBS in pregnant women. However, the presence of commensal bacteria such as Enterococcus faecalis in clinical specimens can inhibit GBS growth in the selective enrichment culture, resulting in false-negative result. Here, we demonstrated that the application of originally isolated endolysin in the enrichment culture improved the test accuracy by inhibiting unwanted E. faecalis growth and therefore avoiding false-negative results, not only in experimental settings, but also in tests using vaginal swabs.
Collapse
Affiliation(s)
- Hidehito Matsui
- Ōmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
| | - Jumpei Uchiyama
- Department of Bacteriology, Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | - Masaya Ogata
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | - Tadahiro Nasukawa
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | | | | | - Hironobu Murakami
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | | | - Hideaki Hanaki
- Ōmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
| |
Collapse
|
17
|
Yin X, Li X, Chen N, Mu L, Wu H, Yang Y, Han K, Huang Y, Wang B, Jian J, Wang A, Ye J. Hemopexin as an acute phase protein regulates the inflammatory response against bacterial infection of Nile tilapia (Oreochromis niloticus). Int J Biol Macromol 2021; 187:166-178. [PMID: 34298052 DOI: 10.1016/j.ijbiomac.2021.07.109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/30/2021] [Accepted: 07/16/2021] [Indexed: 11/18/2022]
Abstract
Hemopexin, a high affinity heme-binding protein is widely involved in variety physiological and pathological processes. It is an important acute phase response protein, and is important in regulating the inflammatory response. In this study, the open reading frame of Nile tilapia hemopexin (OnHpx) gene was amplified. The expression pattern of OnHpx in natural and bacterial challenged tilapia tissues were analyzed through RT-qPCR. The results indicated the OnHpx was most abundant in liver, and increased significantly in liver, spleen, head kidney and peripheral blood after bacterial challenge. Furthermore, the OnHpx mRNA was also significantly up-regulated in monocytes/macrophages and hepatocytes under the stimulation of S. agalactiae or A. hydrophila. In addition, the recombinant OnHpx protein could effectively reduce the bacteria proliferation and alleviate the inflammatory reaction caused by bacteria. Moreover, the (r)OnHpx also regulated the respiratory burst of monocytes/macrophages and played an important role in the antioxidant process. To our knowledge, these results provide the first evidence on the antibacterial and anti-inflammatory response mechanism of Hpx in early vertebrates. This brings new insights about the understanding of the evolutionary origins and ancient roles of the Hpx in the innate immune defense.
Collapse
Affiliation(s)
- Xiaoxue Yin
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China
| | - Xiaoyu Li
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, PR China; State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Life Omics, Beijing 102206, PR China
| | - Nuo Chen
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China
| | - Liangliang Mu
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China.
| | - Hairong Wu
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China
| | - Yanjian Yang
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China
| | - Kailiang Han
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China
| | - Yu Huang
- Guangdong South China Sea Key Laboratory of Aquaculture for Aquatic Economic Animals, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Guangdong Ocean University, Zhanjiang 524088, PR China
| | - Bei Wang
- Guangdong South China Sea Key Laboratory of Aquaculture for Aquatic Economic Animals, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Guangdong Ocean University, Zhanjiang 524088, PR China
| | - Jichang Jian
- Guangdong South China Sea Key Laboratory of Aquaculture for Aquatic Economic Animals, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Guangdong Ocean University, Zhanjiang 524088, PR China
| | - Anli Wang
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China
| | - Jianmin Ye
- School of Life Sciences, South China Normal University, Institute of Modern Aquaculture Science and Engineering, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, Guangzhou 510631, PR China.
| |
Collapse
|
18
|
Hulbah M, Croxen MA, Tyrrell GJ. Phenotypic changes in group B streptococci grown in the presence of the polyols, erythritol, sorbitol and mannitol. BMC Microbiol 2021; 21:145. [PMID: 33985431 PMCID: PMC8117501 DOI: 10.1186/s12866-021-02208-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 04/29/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Group B streptococci (GBS) are important neonatal bacterial pathogens that can cause severe invasive disease in the newborn. It is thought that in many cases of invasive neonatal GBS disease, the bacteria ascend the vagina into the uterus and infect the amniotic fluid surrounding the fetus. Important constituents of this environment include the polyols or sugar alcohols of which erythritol, sorbitol and mannitol are examples. The aim of our study was to investigate the effect of polyols on GBS grown in media containing these sugar alcohols. RESULTS GBS incubated in varying concentrations of polyols (erythritol, sorbitol or mannitol) did not display any significant enhancement or inhibition of bacterial growth. However, growth of GBS in the presence of erythritol significantly increased the surface expression of GBS-PGK (a plasminogen binding protein) 1.25 to 1.5-fold depending on the erythritol concentration and significantly enhanced the survival in human blood 3X to 18X depending on the concentration of polyol used. Interestingly, GBS grown in 1% erythritol significantly increased invasion by the bacteria of HeLa cells (epithelial cell line) (150% vs 100%) however, at higher concentrations (2% or 4% of polyol) the number of CFUs was significantly reduced (55-75% vs 100%) suggesting higher concentrations of polyols may inhibit invasion. Erythritol also increased GBS hemolytic activity as well as enhancing biofilm formation 1.4X to 3.3X depending on the concentration of polyol used. CONCLUSIONS GBS grown in the presence of polyols alters the bacteria's phenotype resulting in changes associated with GBS virulence. This effect was greatest for the polyol erythritol.
Collapse
Affiliation(s)
- Maram Hulbah
- Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Matthew A Croxen
- Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada
- Alberta Precision Laboratories-Public Health, Edmonton, Alberta, T6G 2J2, Canada
| | - Gregory J Tyrrell
- Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.
- Alberta Precision Laboratories-Public Health, Edmonton, Alberta, T6G 2J2, Canada.
| |
Collapse
|
19
|
Zhu N, Zhang C, Prakash A, Hou Z, Liu W, She W, Morris A, Sik Kim K. Therapeutic development of group B Streptococcus meningitis by targeting a host cell signaling network involving EGFR. EMBO Mol Med 2021; 13:e12651. [PMID: 33474818 PMCID: PMC7933950 DOI: 10.15252/emmm.202012651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
Group B Streptococcus (GBS) remains the most common Gram-positive bacterium causing neonatal meningitis and GBS meningitis continues to be an important cause of mortality and morbidity. In this study, we showed that GBS penetration into the brain occurred initially in the meningeal and cortex capillaries, and exploits a defined host cell signaling network comprised of S1P2 , EGFR, and CysLT1. GBS exploitation of such network in penetration of the blood-brain barrier was demonstrated by targeting S1P2 , EGFR, and CysLT1 using pharmacological inhibition, gene knockout and knockdown cells, and gene knockout animals, as well as interrogation of the network (up- and downstream of each other). More importantly, counteracting such targets as a therapeutic adjunct to antibiotic therapy was beneficial in improving the outcome of animals with GBS meningitis. These findings indicate that investigating GBS penetration of the blood-brain barrier provides a novel approach for therapeutic development of GBS meningitis.
Collapse
Affiliation(s)
- Ningyu Zhu
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Chengxian Zhang
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Atish Prakash
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Zheng Hou
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Wei Liu
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Weifeng She
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Andrew Morris
- Division of Cardiovascular MedicineThe Gill Heart InstituteUniversity of KentuckyLexingtonKYUSA
| | - Kwang Sik Kim
- Division of Pediatric Infectious DiseasesJohns Hopkins University School of MedicineBaltimoreMDUSA
| |
Collapse
|
20
|
Diallo K, Feteh VF, Ibe L, Antonio M, Caugant DA, du Plessis M, Deghmane AE, Feavers IM, Fernandez K, Fox LM, Rodrigues CMC, Ronveaux O, Taha MK, Wang X, Brueggemann AB, Maiden MCJ, Harrison OB. Molecular diagnostic assays for the detection of common bacterial meningitis pathogens: A narrative review. EBioMedicine 2021; 65:103274. [PMID: 33721818 PMCID: PMC7957090 DOI: 10.1016/j.ebiom.2021.103274] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 11/29/2022] Open
Abstract
Bacterial meningitis is a major global cause of morbidity and mortality. Rapid identification of the aetiological agent of meningitis is essential for clinical and public health management and disease prevention given the wide range of pathogens that cause the clinical syndrome and the availability of vaccines that protect against some, but not all, of these. Since microbiological culture is complex, slow, and often impacted by prior antimicrobial treatment of the patient, molecular diagnostic assays have been developed for bacterial detection. Distinguishing between meningitis caused by Neisseria meningitidis (meningococcus), Streptococcus pneumoniae (pneumococcus), Haemophilus influenzae, and Streptococcus agalactiae and identifying their polysaccharide capsules is especially important. Here, we review methods used in the identification of these bacteria, providing an up-to-date account of available assays, allowing clinicians and diagnostic laboratories to make informed decisions about which assays to use.
Collapse
Affiliation(s)
- Kanny Diallo
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Cote d'Ivoire
| | - Vitalis F Feteh
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom; Nuffield Department of Population Health, Big Data Institute, University of Oxford, Oxford OX3 7LF, United Kingdom
| | - Lilian Ibe
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom; Nuffield Department of Population Health, Big Data Institute, University of Oxford, Oxford OX3 7LF, United Kingdom
| | - Martin Antonio
- WHO Collaborating Centre for New Vaccines Surveillance, Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, PO Box 273, Banjul, Gambia; Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Dominique A Caugant
- WHO Collaborating Center for Reference and Research on Meningococci, Norwegian Institute of Public Health, Oslo N-0213, Norway
| | - Mignon du Plessis
- A division of the National Health Laboratory Service (NHLS), National Institute for Communicable Diseases (NICD), Johannesburg, South Africa
| | | | - Ian M Feavers
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom
| | | | - LeAnne M Fox
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Division of Bacterial Diseases, Meningitis and Vaccine Preventable Diseases Branch, United States
| | - Charlene M C Rodrigues
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom; Department of Paediatric Infectious Diseases, St George's University Hospitals NHS Foundation Trust, London, United Kingdom
| | | | | | - Xin Wang
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Division of Bacterial Diseases, Meningitis and Vaccine Preventable Diseases Branch, United States
| | - Angela B Brueggemann
- Nuffield Department of Population Health, Big Data Institute, University of Oxford, Oxford OX3 7LF, United Kingdom
| | - Martin C J Maiden
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom
| | - Odile B Harrison
- Department of Zoology, University of Oxford, South Parks Rd, Oxford OX1 3SY, United Kingdom.
| |
Collapse
|
21
|
Manne K, Chattopadhyay D, Agarwal V, Blom AM, Khare B, Chakravarthy S, Chang C, Ton-That H, Narayana SVL. Novel structure of the N-terminal helical domain of BibA, a group B streptococcus immunogenic bacterial adhesin. Acta Crystallogr D Struct Biol 2020; 76:759-770. [PMID: 32744258 PMCID: PMC7397492 DOI: 10.1107/s2059798320008116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/17/2020] [Indexed: 11/10/2022] Open
Abstract
BibA, a group B streptococcus (GBS) surface protein, has been shown to protect the pathogen from phagocytic killing by sequestering a complement inhibitor: C4b-binding protein (C4BP). Here, the X-ray crystallographic structure of a GBS BibA fragment (BibA126-398) and a low-resolution small-angle X-ray scattering (SAXS) structure of the full-length N-terminal domain (BibA34-400) are described. The BibA126-398 fragment crystal structure displayed a novel and predominantly helical structure. The tertiary arrangement of helices forms four antiparallel three-helix-bundle-motif repeats, with one long helix from a bundle extending into the next. Multiple mutations on recombinant BibA34-400 delayed the degradation of the protein, and circular dichroism spectroscopy of BibA34-400 suggested a similar secondary-structure composition to that observed in the crystallized BibA126-398 fragment. A model was generated for the 92 N-terminal residues (BibA34-125) using structural similarity prediction programs, and a BibA34-400 model was generated by combining the coordinates of BibA34-126 and BibA126-398. The X-ray structure of BibA126-398 and the model of BibA34-400 fitted well into the calculated SAXS envelope. One possible binding site for the BibA N-terminal domain was localized to the N-terminal CCP (complement-control protein) domains of the C4BP α-chain, as indicated by the decreased binding of BibA to a ΔCCP1 C4BP α-chain mutant. In summary, it is suggested that the GBS surface protein BibA, which consists of three antiparallel α-helical-bundle motifs, is unique and belongs to a new class of Gram-positive surface adhesins.
Collapse
Affiliation(s)
- Kartik Manne
- Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birningham, AL 35294, USA
| | | | - Vaibhav Agarwal
- Department of Translational Medicine, Lund University, S-214 28 Malmö, Sweden
| | - Anna M. Blom
- Department of Translational Medicine, Lund University, S-214 28 Malmö, Sweden
| | - Baldeep Khare
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Chungyu Chang
- Division of Oral Biology and Medicine, School of Dentistry, University of California Los Angeles, Los Angeles, California, USA
| | - Hung Ton-That
- Division of Oral Biology and Medicine, School of Dentistry, University of California Los Angeles, Los Angeles, California, USA
| | - Sthanam V. L. Narayana
- Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birningham, AL 35294, USA
| |
Collapse
|
22
|
Cao Q, Ma K, Nie M, Dong Y, Lu C, Liu Y. Role of luxS in immune evasion and pathogenicity of piscine Streptococcus agalactiae is not dependent on autoinducer-2. Fish Shellfish Immunol 2020; 99:274-283. [PMID: 32058098 DOI: 10.1016/j.fsi.2020.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 06/10/2023]
Abstract
luxS-mediated autoinducer 2 (AI-2)-dependent quorum sensing (QS) has been demonstrated to affect many bacterial phenotypes, including virulence. Streptococcus agalactiae harbors a functional luxS gene required for the biosynthesis of AI-2. In this study, we investigated the regulation effect and mechanism of the luxS/AI-2 QS system in the pathogenicity of the piscine S. agalactiae strain GD201008-001. We found that inactivation of luxS caused a marked decrease in biofilm formation, hemolytic activity, antiphagocytosis and intracellular survival of S. agalactiae. Except for hemolytic activity, the altered phenotypes due to the luxS deletion were AI-2-independent. Further investigation indicated that high levels of the proinflammatory cytokines IL-1β and IL-6 could be induced in macrophages co-incubated with the luxS deletion mutant and synthetic AI-2, single or combined. Also, the results of tilapia infection showed that inactivation of luxS significantly decreased the virulence of S. agalactiae but upregulated the expression of cytokines in spleens and brains. Increased proinflammatory effects of the luxS mutant were restored in the luxS complemented strain but could not be restored by AI-2 addition. All the findings suggest that luxS is involved in virulence-associated phenotypes and immunological evasion of S. agalactiae, and furthermore, this involvement is mostly AI-2-independent. This study will provide valuable insights into our understanding of the role of the LuxS/AI-2 QS system in the pathogenesis of S. agalactiae.
Collapse
Affiliation(s)
- Qing Cao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ke Ma
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Meng Nie
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
| |
Collapse
|
23
|
Chambers SA, Moore RE, Craft KM, Thomas HC, Das R, Manning SD, Codreanu SG, Sherrod SD, Aronoff DM, McLean JA, Gaddy JA, Townsend SD. A Solution to Antifolate Resistance in Group B Streptococcus: Untargeted Metabolomics Identifies Human Milk Oligosaccharide-Induced Perturbations That Result in Potentiation of Trimethoprim. mBio 2020; 11:e00076-20. [PMID: 32184236 PMCID: PMC7078465 DOI: 10.1128/mbio.00076-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 01/30/2020] [Indexed: 01/21/2023] Open
Abstract
Adjuvants can be used to potentiate the function of antibiotics whose efficacy has been reduced by acquired or intrinsic resistance. In the present study, we discovered that human milk oligosaccharides (HMOs) sensitize strains of group B Streptococcus (GBS) to trimethoprim (TMP), an antibiotic to which GBS is intrinsically resistant. Reductions in the MIC of TMP reached as high as 512-fold across a diverse panel of isolates. To better understand HMOs' mechanism of action, we characterized the metabolic response of GBS to HMO treatment using ultrahigh-performance liquid chromatography-high-resolution tandem mass spectrometry (UPLC-HRMS/MS) analysis. These data showed that when challenged by HMOs, GBS undergoes significant perturbations in metabolic pathways related to the biosynthesis and incorporation of macromolecules involved in membrane construction. This study represents reports the metabolic characterization of a cell that is perturbed by HMOs.IMPORTANCE Group B Streptococcus is an important human pathogen that causes serious infections during pregnancy which can lead to chorioamnionitis, funisitis, premature rupture of gestational membranes, preterm birth, neonatal sepsis, and death. GBS is evolving antimicrobial resistance mechanisms, and the work presented in this paper provides evidence that prebiotics such as human milk oligosaccharides can act as adjuvants to restore the utility of antibiotics.
Collapse
Affiliation(s)
| | - Rebecca E Moore
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Kelly M Craft
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Harrison C Thomas
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Rishub Das
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Shannon D Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Simona G Codreanu
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Center for Innovative Technology, Nashville, Tennessee, USA
| | - Stacy D Sherrod
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Center for Innovative Technology, Nashville, Tennessee, USA
| | - David M Aronoff
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John A McLean
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Center for Innovative Technology, Nashville, Tennessee, USA
| | - Jennifer A Gaddy
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare Systems, Nashville, Tennessee, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Steven D Townsend
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
24
|
Xu J, Xie YD, Liu L, Guo S, Su YL, Li AX. Virulence regulation of cel-EIIB protein mediated PTS system in Streptococcus agalactiae in Nile tilapia. J Fish Dis 2019; 42:11-19. [PMID: 30374993 DOI: 10.1111/jfd.12907] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 06/08/2023]
Abstract
Streptococcus agalactiae is a major pathogen of tilapia causing significant economic losses for the global aquatic industry yearly. To elucidate the role of cel-EIIB protein-mediated phosphotransferase systems (PTS) in the virulence regulation of S. agalactiae, cel-EIIB gene deletion in a virulent strain THN0901 was achieved by homologous recombination. The cellobiose utilization of △cel-EIIB strain was significantly decreased relative to S.a.THN0901 strain incubating in LB with 10 mg/ml cellobiose (p < 0.05). The biofilm formation ability of △cel-EIIB strain was also significantly decreased when cultured in BHI medium (p < 0.05). Under a lower infection dose, the accumulative mortality of tilapia caused by △cel-EIIB strain was dramatically decreased (20%), of which S.a.THN0901 strain and △cel-EIIB::i strain were 53.33% and 50%, respectively. The competition experience using tilapia model indicated the invasion and colonization ability of △cel-EIIB strain was significantly weaker than that of S.a.THN0901 strain (p < 0.05). Compared to △cel-EIIB::i strain, the mRNA expression of csrS, csrR, rgfA, rgfC, bgrR and bgrS was significantly downregulated in △cel-EIIB strain (p < 0.05). In conclusion, cel-EIIB protein-mediated cel-PTS not only contributes to biofilm formation and virulence regulation, but also plays an important role in the invasion and colonization of S. agalactiae.
Collapse
Affiliation(s)
- Jun Xu
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Lab for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yun-Dan Xie
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong Province, China
| | - Ling Liu
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Lab for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Song Guo
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Lab for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - You-Lu Su
- College of Fisheries, Tianjin Agricultural University, Tianjin, China
| | - An-Xing Li
- State Key Laboratory of Biocontrol/Guangdong Provincial Key Lab for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| |
Collapse
|
25
|
Zhang H, Jiang H, Fan Y, Chen Z, Li M, Mao Y, Karrow NA, Loor JJ, Moore S, Yang Z. Transcriptomics and iTRAQ-Proteomics Analyses of Bovine Mammary Tissue with Streptococcus agalactiae-Induced Mastitis. J Agric Food Chem 2018; 66:11188-11196. [PMID: 30096236 DOI: 10.1021/acs.jafc.8b02386] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Mastitis is a highly prevalent disease in dairy cows that causes large economic losses. Streptococcus agalactiae is a common contagious pathogen and a major cause of bovine mastitis. The immune response to intramammary infection with S. agalactiae in dairy cows is a very complex biological process. To understand the host immune response to S. agalactiae-induced mastitis, mammary gland of lactating Chinese Holstein cows was challenged with S. agalactiae via nipple tube perfusion. Visual inspection, analysis of milk somatic cell counts, histopathology, and transmission electron microscopy of mammary tissue were performed to confirm S. agalactiae-induced mastitis. Microarray and isobaric tags for relative and absolute quantitation (iTRAQ) were used to compare the transcriptomes and proteomes of healthy and mastitic mammary tissue. Compared with healthy tissue, a total of 129 differentially expressed genes (DEGs, fold change >2, p < 0.05) and 144 differentially expressed proteins (DEPs, fold change >1.2, p < 0.05) were identified in mammary tissue from S. agalactiae-challenged cows. Among the concordant 18 DEGs/DEPs, immunoglobulin M precursor, cathelicidin-7 precursor, integrin alpha-5, and complement C4-A-like isoform X1 were associated with mastitis. Intramammary infection with S. agalactiae triggered a complex host innate immune response that involved complement and coagulation cascades, ECM-receptor interaction, focal adhesion, and phagosome and bacterial invasion of epithelial cells pathways. These results provide candidate genes or proteins for further studies in the context of prevention and targeted treatment of bovine mastitis.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Niel A Karrow
- Department of Animal Biosciences , University of Guelph , Guelph N1G 2W1 , Canada
| | - Juan J Loor
- Department of Animal Sciences & Division of Nutritional Sciences , University of Illinois , Urbana , Illinois 61801 , United States
| | - Stephen Moore
- Centre for Animal Science , University of Queensland , Saint Luci , Queensland 4072a , Australia
| | | |
Collapse
|
26
|
Tomazi T, de Souza Filho AF, Heinemann MB, dos Santos MV. Molecular characterization and antimicrobial susceptibility pattern of Streptococcus agalactiae isolated from clinical mastitis in dairy cattle. PLoS One 2018; 13:e0199561. [PMID: 29928042 PMCID: PMC6013152 DOI: 10.1371/journal.pone.0199561] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/08/2018] [Indexed: 12/12/2022] Open
Abstract
The objectives of this study were to: (a) genotypically characterize Streptococcus agalactiae isolates recovered from clinical mastitis (CM) cases in dairy cows and, (b) determine the association of antimicrobial susceptibility (AMS) and genotypes of Strep. agalactiae clustered according to the genetic similarity. A total of 89 Strep. agalactiae isolates recovered from bovine CM were genotyped using random amplified polymorphic DNA (RAPD) analysis. In addition, the AMS of the isolates was determined using a commercial broth microdilution test composed of 10 antimicrobials (penicillin, ampicillin, oxacillin, cephalothin, ceftiofur, penicillin/novobiocin, erythromycin, pirlimycin, tetracycline, and sulfadimethoxine). Descriptive analysis was used to report the frequency of RAPD-types and genotypic clusters within herd, housing system, season and CM severity scores. The minimal antimicrobial concentrations that inhibited 50% (MIC50) and 90% (MIC90) of the isolates were calculated and survival analysis was completed to verify the differences of AMS among genotypic clusters. Results of RAPD showed a great genotypic diversity of Strep. agalactiae (45 RAPD-types) and three clusters (Ia, Ib and II) were created based on the genetic similarity among genotypes. After clustering, a high genetic similarity was observed within and between herds. Overall, Strep. agalactiae showed high susceptibility to most antimicrobials, except to tetracycline and erythromycin. Differences in the AMS among clusters were observed for ampicillin, ceftiofur, erythromycin, pirlimycin, sulfadimethoxine and tetracycline. In conclusion, Strep. agalactiae is still highly susceptible to most antimicrobials, although differences in susceptibility to certain antimicrobials were observed among genotypic clusters.
Collapse
Affiliation(s)
- Tiago Tomazi
- Department of Animal Production and Nutrition, Milk Quality Research Laboratory (Qualileite), University of São Paulo, Pirassununga, Brazil
| | - Antonio Francisco de Souza Filho
- Department of Preventive Veterinary Medicine and Animal Health, Laboratory of Bacterial Zoonosis, University of São Paulo, São Paulo, Brazil
| | - Marcos Bryan Heinemann
- Department of Preventive Veterinary Medicine and Animal Health, Laboratory of Bacterial Zoonosis, University of São Paulo, São Paulo, Brazil
| | - Marcos Veiga dos Santos
- Department of Animal Production and Nutrition, Milk Quality Research Laboratory (Qualileite), University of São Paulo, Pirassununga, Brazil
- * E-mail:
| |
Collapse
|
27
|
Devaux L, Sleiman D, Mazzuoli MV, Gominet M, Lanotte P, Trieu-Cuot P, Kaminski PA, Firon A. Cyclic di-AMP regulation of osmotic homeostasis is essential in Group B Streptococcus. PLoS Genet 2018; 14:e1007342. [PMID: 29659565 PMCID: PMC5919688 DOI: 10.1371/journal.pgen.1007342] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/26/2018] [Accepted: 03/28/2018] [Indexed: 02/03/2023] Open
Abstract
Cyclic nucleotides are universally used as secondary messengers to control cellular physiology. Among these signalling molecules, cyclic di-adenosine monophosphate (c-di-AMP) is a specific bacterial second messenger recognized by host cells during infections and its synthesis is assumed to be necessary for bacterial growth by controlling a conserved and essential cellular function. In this study, we sought to identify the main c-di-AMP dependent pathway in Streptococcus agalactiae, the etiological agent of neonatal septicaemia and meningitis. By conditionally inactivating dacA, the only diadenyate cyclase gene, we confirm that c-di-AMP synthesis is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable due to the accumulation of compensatory mutations. We identified several mutations restoring the viability of a ΔdacA mutant, in particular a loss-of-function mutation in the osmoprotectant transporter BusAB. Identification of c-di-AMP binding proteins revealed a conserved set of potassium and osmolyte transporters, as well as the BusR transcriptional factor. We showed that BusR negatively regulates busAB transcription by direct binding to the busAB promoter. Loss of BusR repression leads to a toxic busAB expression in absence of c-di-AMP if osmoprotectants, such as glycine betaine, are present in the medium. In contrast, deletion of the gdpP c-di-AMP phosphodiesterase leads to hyperosmotic susceptibility, a phenotype dependent on a functional BusR. Taken together, we demonstrate that c-di-AMP is essential for osmotic homeostasis and that the predominant mechanism is dependent on the c-di-AMP binding transcriptional factor BusR. The regulation of osmotic homeostasis is likely the conserved and essential function of c-di-AMP, but each species has evolved specific c-di-AMP mechanisms of osmoregulation to adapt to its environment. Nucleotide-based second messengers play central functions in bacterial physiology and host-pathogen interactions. Among these signalling nucleotides, cyclic-di-AMP (c-di-AMP) synthesis was originally assumed to be essential for bacterial growth. In this study, we confirmed that the only di-adenylate cyclase enzyme in the opportunistic pathogen Streptococcus agalactiae is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable by accumulating spontaneous mutations in genes involved in osmotic regulation. We identified that c-di-AMP binds directly to four proteins necessary to maintain osmotic homeostasis, including three osmolyte transporters and the BusR transcriptional factor. We demonstrated that BusR negatively controls the expression of the busAB operon and that it is the main component leading to growth inhibition in the absence of c-di-AMP synthesis if osmoprotectants are present in the environment. Overall, c-di-AMP is essential to maintain osmotic homeostasis by coordinating osmolyte uptake and thus bacteria have developed specific mechanisms to keep c-di-AMP as the central regulator of osmotic homeostasis.
Collapse
Affiliation(s)
- Laura Devaux
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Dona Sleiman
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Maria-Vittoria Mazzuoli
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Myriam Gominet
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Philippe Lanotte
- Université de Tours, Infectiologie et Santé Publique, Bactéries et Risque Materno-Fœtal, INRA UMR1282, Tours France
- Hôpital Bretonneau, Centre Hospitalier Régional et Universitaire de Tours, Service de Bactériologie-Virologie, Tours France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- * E-mail:
| |
Collapse
|
28
|
Teatero S, Neemuchwala A, Yang K, Gomes J, Athey TBT, Martin I, Demczuk W, McGeer A, Fittipaldi N. Genetic evidence for a novel variant of the pilus island 1 backbone protein in group B Streptococcus. J Med Microbiol 2017; 66:1409-1415. [PMID: 28923133 DOI: 10.1099/jmm.0.000588] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Pili contribute significantly to the pathogenesis of infection of group B Streptococcus (GBS) by facilitating adhesion and invasion of host cells. GBS pilin subunits (the backbone pilin protein, BP, and the ancillary pilin proteins, AP) as well as the specific enzymes required for pilus assembly are encoded by genes located in two separate genomic regions, known as pilus island 1 (PI-1) and PI-2. Our aim was to characterize the pilus profile of a collection of GBS isolates from metropolitan Toronto, Canada. METHODOLOGY The pilus profile of 1332 invasive and colonizing GBS isolates was determined by PCR and, in selected cases, by whole genome sequencing. RESULTS While investigating the pilus profile of a collection of GBS organisms, we discovered that 51 isolates possessed a novel variant of the PI-1 BP, which we named BP-1b. The predicted translated sequences of archetypical GBS BP-1 and novel BP-1b variants shared only 63 % amino acid sequence homology. The novel BP-1b variant was most common among strains of serotype Ib and VI, but was also found among strains of serotypes Ia, II, III and VIII. CONCLUSION We describe a relatively frequent occurrence of a novel PI-1 BP that cannot be detected by a commonly used multiplex PCR scheme, which could lead to strains being mistyped as PI-1 negative. We present PCR primers that can easily be incorporated into the multiplex PCR assay to identify strains with novel BP-1b variant.
Collapse
Affiliation(s)
| | | | | | | | | | - Irene Martin
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Walter Demczuk
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Allison McGeer
- Sinai Health System, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nahuel Fittipaldi
- Public Health Ontario, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
29
|
Kim HW, Lee JH, Cho HK, Lee H, Seo HS, Lee S, Kim KH. Opsonophagocytic Antibodies to Serotype Ia, Ib, and III Group B Streptococcus among Korean Infants and in Intravenous Immunoglobulin Products. J Korean Med Sci 2017; 32:737-743. [PMID: 28378545 PMCID: PMC5383604 DOI: 10.3346/jkms.2017.32.5.737] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 01/27/2017] [Indexed: 11/20/2022] Open
Abstract
Group B streptococcus (GBS) infection is a leading cause of sepsis and meningitis among infants, and is associated with high rates of morbidity and mortality in many countries. Protection against GBS typically involves antibody-mediated opsonization by phagocytes and complement components. The present study evaluated serotype-specific functional antibodies to GBS among Korean infants and in intravenous immunoglobulin (IVIG) products. An opsonophagocytic killing assay (OPA) was used to calculate the opsonization indices (OIs) of functional antibodies to serotypes Ia, Ib, and III in 19 IVIG products from 5 international manufacturers and among 98 Korean infants (age: 0-11 months). The GBS Ia, Ib, and III serotypes were selected because they are included in a trivalent GBS vaccine formulation that is being developed. The OI values for the IVIG products were 635-5,706 (serotype Ia), 488-1,421 (serotype Ib), and 962-3,315 (serotype III), and none of the IVIG lots exhibited undetectable OI values (< 4). The geometric mean OI values were similar for all 3 serotypes when we compared the Korean manufacturers. The seropositive rate among infants was significantly lower for serotype Ia (18.4%), compared to serotype Ib and serotype III (both, 38.8%). Infant age of ≥ 3 months was positively correlated with the seropositive rates for each serotype. Therefore, only a limited proportion of infants exhibited protective immunity against serotype Ia, Ib, and III GBS infections. IVIG products that exhibit high antibody titers may be a useful therapeutic or preventive measure for infants. Further studies are needed to evaluate additional serotypes and age groups.
Collapse
Affiliation(s)
- Han Wool Kim
- Center for Vaccine Evaluation and Study, Medical Research Institute, Ewha Womans University School of Medicine, Seoul, Korea
| | - Ji Hyen Lee
- Center for Vaccine Evaluation and Study, Medical Research Institute, Ewha Womans University School of Medicine, Seoul, Korea
- Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, Korea
| | - Hye Kyung Cho
- Department of Pediatrics, Graduate School of Medicine, Gachon University, Incheon, Korea
| | - Hyunju Lee
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea
| | - Ho Seong Seo
- Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup, Korea
| | - Soyoung Lee
- Center for Vaccine Evaluation and Study, Medical Research Institute, Ewha Womans University School of Medicine, Seoul, Korea
| | - Kyung Hyo Kim
- Center for Vaccine Evaluation and Study, Medical Research Institute, Ewha Womans University School of Medicine, Seoul, Korea
- Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, Korea.
| |
Collapse
|
30
|
Khosa S, Hoeppner A, Gohlke H, Schmitt L, Smits SHJ. Structure of the Response Regulator NsrR from Streptococcus agalactiae, Which Is Involved in Lantibiotic Resistance. PLoS One 2016; 11:e0149903. [PMID: 26930060 PMCID: PMC4773095 DOI: 10.1371/journal.pone.0149903] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/05/2016] [Indexed: 01/22/2023] Open
Abstract
Lantibiotics are antimicrobial peptides produced by Gram-positive bacteria. Interestingly, several clinically relevant and human pathogenic strains are inherently resistant towards lantibiotics. The expression of the genes responsible for lantibiotic resistance is regulated by a specific two-component system consisting of a histidine kinase and a response regulator. Here, we focused on a response regulator involved in lantibiotic resistance, NsrR from Streptococcus agalactiae, and determined the crystal structures of its N-terminal receiver domain and C-terminal DNA-binding effector domain. The C-terminal domain exhibits a fold that classifies NsrR as a member of the OmpR/PhoB subfamily of regulators. Amino acids involved in phosphorylation, dimerization, and DNA-binding were identified and demonstrated to be conserved in lantibiotic resistance regulators. Finally, a model of the full-length NsrR in the active and inactive state provides insights into protein dimerization and DNA-binding.
Collapse
Affiliation(s)
- Sakshi Khosa
- Institute of Biochemistry, Heinrich Heine University Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Astrid Hoeppner
- X-Ray Facility and Crystal Farm, Heinrich Heine University Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Holger Gohlke
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Sander H. J. Smits
- Institute of Biochemistry, Heinrich Heine University Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
- * E-mail:
| |
Collapse
|
31
|
Su YL, Feng J, Li YW, Bai JS, Li AX. Development of a quantitative PCR assay for monitoring Streptococcus agalactiae colonization and tissue tropism in experimentally infected tilapia. J Fish Dis 2016; 39:229-238. [PMID: 25858765 DOI: 10.1111/jfd.12358] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/10/2015] [Accepted: 01/10/2015] [Indexed: 06/04/2023]
Abstract
Streptococcus agalactiae has become one of the most important emerging pathogens in the aquaculture industry and has resulted in large economic losses for tilapia farms in China. In this study, three pairs of specific primers were designed and tested for their specificities and sensitivities in quantitative real-time polymerase chain reactions (qPCRs) after optimization of the annealing temperature. The primer pair IGS-s/IGS-a, which targets the 16S-23S rRNA intergenic spacer region, was finally chosen, having a detection limit of 8.6 copies of S. agalactiae DNA in a 20 μL reaction mixture. Bacterial tissue tropism was demonstrated by qPCR in Oreochromis niloticus 5 days post-injection with a virulent S. agalactiae strain. Bacterial loads were detected at the highest level in brain, followed by moderately high levels in kidney, heart, spleen, intestines, and eye. Significantly lower bacterial loads were observed in muscle, gill and liver. In addition, significantly lower bacterial loads were observed in the brain of convalescent O. niloticus 14 days post-injection with several different S. agalactiae strains. The qPCR for the detection of S. agalactiae developed in this study provides a quantitative tool for investigating bacterial tissue tropism in infected fish, as well as for monitoring bacterial colonization in convalescent fish.
Collapse
Affiliation(s)
- Y-L Su
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Haizhu District, Guangzhou, Guangdong Province, China
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong Province, China
| | - J Feng
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong Province, China
| | - Y-W Li
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Haizhu District, Guangzhou, Guangdong Province, China
| | - J-S Bai
- Guangzhou Airport Extry-Exit Inspection and Quarantine Bureau, Guangzhou, Guangdong Province, China
| | - A-X Li
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Haizhu District, Guangzhou, Guangdong Province, China
| |
Collapse
|
32
|
Liu G, Zhu J, Shi Z, Ding M, Wang R, Yao H, Lu C, Xu P. [Effect of the 10 kb sequence of piscine Streptococcus agalactiae on bacterial virulence]. Wei Sheng Wu Xue Bao 2016; 56:110-119. [PMID: 27305785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
OBJECTIVE From the previous comparative genomic analysis, we found a specific unknown 10 kb sequence (including 11 Open reading Frames) in Chinese piscine strain GD201008-001 genome. To study the role of 10 kb in the pathogenicity of piscine S. agalactiae, the 10 kb sequence was deleted from the GD201008-001 genome. METHODS The isogenic mutant Δ10 kb was constructed by using the temperature-sensitive Streptococcus-E. coli shuttle vector pSET4s. We compared the growth characteristics, adherence to HEp-2 cell and bacterial virulence in a zebrafish infection model between wild strain and mutant. Meanwhile the expressions of the known virulence genes from GD201008-001 and Δ10 kb were also quantified by real-time PCR. RESULTS The Δ10 kb showed no significant differences in bacterial morphology and adherence to HEp-2 cells compared with the wild-type strain, but the speed of growth was slightly slower than the wild strain. Furthermore the 50% lethal dose of Δ10 kb was decreased up to 10-fold (P < 0.001) of the parental strain in a zebrafish infection model, and the expressions of the virulence genes, PI-2b and neul, were significantly increased in the mutant. CONCLUSION These findings demonstrated that the 10 kb sequence of piscine Streptococcus agalactiae exerts a significant effect on bacterial virulence and probably regulates the virulence genes expression of GD20 1008-001.
Collapse
|
33
|
Ipe DS, Ben Zakour NL, Sullivan MJ, Beatson SA, Ulett KB, Benjamin WH, Davies MR, Dando SJ, King NP, Cripps AW, Schembri MA, Dougan G, Ulett GC. Discovery and Characterization of Human-Urine Utilization by Asymptomatic-Bacteriuria-Causing Streptococcus agalactiae. Infect Immun 2016; 84:307-19. [PMID: 26553467 PMCID: PMC4694007 DOI: 10.1128/iai.00938-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/01/2015] [Indexed: 12/27/2022] Open
Abstract
Streptococcus agalactiae causes both symptomatic cystitis and asymptomatic bacteriuria (ABU); however, growth characteristics of S. agalactiae in human urine have not previously been reported. Here, we describe a phenotype of robust growth in human urine observed in ABU-causing S. agalactiae (ABSA) that was not seen among uropathogenic S. agalactiae (UPSA) strains isolated from patients with acute cystitis. In direct competition assays using pooled human urine inoculated with equal numbers of a prototype ABSA strain, designated ABSA 1014, and any one of several UPSA strains, measurement of the percentage of each strain recovered over time showed a markedly superior fitness of ABSA 1014 for urine growth. Comparative phenotype profiling of ABSA 1014 and UPSA strain 807, isolated from a patient with acute cystitis, using metabolic arrays of >2,500 substrates and conditions revealed unique and specific l-malic acid catabolism in ABSA 1014 that was absent in UPSA 807. Whole-genome sequencing also revealed divergence in malic enzyme-encoding genes between the strains predicted to impact the activity of the malate metabolic pathway. Comparative growth assays in urine comparing wild-type ABSA and gene-deficient mutants that were functionally inactivated for the malic enzyme metabolic pathway by targeted disruption of the maeE or maeK gene in ABSA demonstrated attenuated growth of the mutants in normal human urine as well as synthetic human urine containing malic acid. We conclude that some S. agalactiae strains can grow in human urine, and this relates in part to malic acid metabolism, which may affect the persistence or progression of S. agalactiae ABU.
Collapse
Affiliation(s)
- Deepak S Ipe
- School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia
| | - Nouri L Ben Zakour
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Matthew J Sullivan
- School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Kimberly B Ulett
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - William H Benjamin
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Mark R Davies
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Samantha J Dando
- Institute for Glycomics, Griffith University, Gold Coast Campus, QLD, Australia
| | - Nathan P King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Allan W Cripps
- School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Glen C Ulett
- School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
34
|
Khosa S, Hoeppner A, Kleinschrodt D, Smits SHJ. Overexpression, purification and crystallization of the response regulator NsrR involved in nisin resistance. Acta Crystallogr F Struct Biol Commun 2015; 71:1322-6. [PMID: 26457525 PMCID: PMC4601598 DOI: 10.1107/s2053230x15016441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/03/2015] [Indexed: 11/10/2022] Open
Abstract
A number of Gram-positive bacteria produce a class of bacteriocins called `lantibiotics'. These lantibiotics are ribosomally synthesized peptides that possess high antimicrobial activity against Gram-positive bacteria, including clinically challenging pathogens, and are therefore potential alternatives to antibiotics. All lantibiotic producer strains and some Gram-positive nonproducer strains express protein systems to circumvent a suicidal effect or to become resistant, respectively. Two-component systems consisting of a response regulator and a histidine kinase upregulate the expression of these proteins. One of the best-characterized lantibiotics is nisin, which is produced by Lactococcus lactis and possesses bactericidal activity against various Gram-positive bacteria, including some human pathogenic strains. Within many human pathogenic bacterial strains inherently resistant to nisin, a response regulator, NsrR, has been identified which regulates the expression of proteins involved in nisin resistance. In the present study, an expression and purification protocol was established for the NsrR protein from Streptococcus agalactiae COH1. The protein was successfully crystallized using the vapour-diffusion method, resulting in crystals that diffracted X-rays to 1.4 Å resolution.
Collapse
Affiliation(s)
- Sakshi Khosa
- Institute of Biochemistry, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Astrid Hoeppner
- Crystal Farm and X-ray Facility, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Diana Kleinschrodt
- Protein Production Facility, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Sander H. J. Smits
- Institute of Biochemistry, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| |
Collapse
|
35
|
Morello E, Mallet A, Konto-Ghiorghi Y, Chaze T, Mistou MY, Oliva G, Oliveira L, Di Guilmi AM, Trieu-Cuot P, Dramsi S. Evidence for the Sialylation of PilA, the PI-2a Pilus-Associated Adhesin of Streptococcus agalactiae Strain NEM316. PLoS One 2015; 10:e0138103. [PMID: 26407005 PMCID: PMC4583379 DOI: 10.1371/journal.pone.0138103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/25/2015] [Indexed: 01/20/2023] Open
Abstract
Streptococcus agalactiae (or Group B Streptococcus, GBS) is a commensal bacterium present in the intestinal and urinary tracts of approximately 30% of humans. We and others previously showed that the PI-2a pilus polymers, made of the backbone pilin PilB, the tip adhesin PilA and the cell wall anchor protein PilC, promote adhesion to host epithelia and biofilm formation. Affinity-purified PI-2a pili from GBS strain NEM316 were recognized by N-acetylneuraminic acid (NeuNAc, also known as sialic acid) specific lectins such as Elderberry Bark Lectin (EBL) suggesting that pili are sialylated. Glycan profiling with twenty different lectins combined with monosaccharide composition by HPLC suggested that affinity-purified PI-2a pili are modified by N-glycosylation and decorated with sialic acid attached to terminal galactose. Analysis of various relevant mutants in the PI-2a pilus operon by flow-cytometry and electron microscopy analyses pointed to PilA as the pilus subunit modified by glycosylation. Double labeling using PilB antibody and EBL lectin, which specifically recognizes N-acetylneuraminic acid attached to galactose in α-2, 6, revealed a characteristic binding of EBL at the tip of the pilus structures, highly reminiscent of PilA localization. Expression of a secreted form of PilA using an inducible promoter showed that this recombinant PilA binds specifically to EBL lectin when produced in the native GBS context. In silico search for potentially glycosylated asparagine residues in PilA sequence pointed to N427 and N597, which appear conserved and exposed in the close homolog RrgA from S. pneumoniae, as likely candidates. Conversion of these two asparagyl residues to glutamyl resulted in a higher instability of PilA. Our results provide the first evidence that the tip PilA adhesin can be glycosylated, and suggest that this modification is critical for PilA stability and may potentially influence interactions with the host.
Collapse
Affiliation(s)
- Eric Morello
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Adeline Mallet
- Institut Pasteur, Imagopole, Ultrastructural Microscopy Platform, Paris, France
| | - Yoan Konto-Ghiorghi
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Thibault Chaze
- Institut Pasteur, Spectrométrie de Masse Structurale et Protéomique, Paris, France
- INRA UMR 1319, MICALIS, Jouy-en-Josas, France
| | | | - Giulia Oliva
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Liliana Oliveira
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Anne-Marie Di Guilmi
- Université Grenoble Alpes, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité des Bactéries Pathogènes à Gram positif, Paris, France
- Centre National de la Recherche Scientifique (CNRS ERL 3526), Paris, France
- * E-mail:
| |
Collapse
|
36
|
Vasilyeva A, Santos Sanches I, Florindo C, Dmitriev A. Natural Mutations in Streptococcus agalactiae Resulting in Abrogation of β Antigen Production. PLoS One 2015; 10:e0128426. [PMID: 26047354 PMCID: PMC4457541 DOI: 10.1371/journal.pone.0128426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/27/2015] [Indexed: 11/18/2022] Open
Abstract
Streptococcus agalactiae genome encodes 21 two-component systems (TCS) and a variety of regulatory proteins in order to control gene expression. One of the TCS, BgrRS, comprising the BgrR DNA-binding regulatory protein and BgrS sensor histidine kinase, was discovered within a putative virulence island. BgrRS influences cell metabolism and positively control the expression of bac gene, coding for β antigen at transcriptional level. Inactivation of bgrR abrogated bac gene expression and increased virulence properties of S. agalactiae. In this study, a total of 140 strains were screened for the presence of bac gene, and the TCS bgrR and bgrS genes. A total of 53 strains carried the bac, bgrR and bgrS genes. Most of them (48 strains) expressed β antigen, while five strains did not express β antigen. Three strains, in which bac gene sequence was intact, while bgrR and/or bgrS genes had mutations, and expression of β antigen was absent, were complemented with a constructed plasmid pBgrRS(P) encoding functionally active bgrR and bgrS gene alleles. This procedure restored expression of β antigen indicating the crucial regulatory role of TCS BgrRS. The complemented strain A49V/BgrRS demonstrated attenuated virulence in intraperitoneal mice model of S. agalactiae infection compared to parental strain A49V. In conclusion we showed that disruption of β antigen expression is associated with: i) insertion of ISSa4 upstream the bac gene just after the ribosomal binding site; ii) point mutation G342A resulting a stop codon TGA within the bac gene and a truncated form of β antigen; iii) single deletion (G) in position 439 of the bgrR gene resulting in a frameshift and the loss of DNA-binding domain of the BgrR protein, and iv) single base substitutions in bgrR and bgrS genes causing single amino acid substitutions in BgrR (Arg187Lys) and BgrS (Arg252Gln). The fact that BgrRS negatively controls virulent properties of S. agalactiae gives a novel clue for understanding of S. agalactiae adaptation to the human.
Collapse
Affiliation(s)
- Anastasia Vasilyeva
- Department of Molecular Microbiology, Institute of Experimental Medicine, Saint-Petersburg, Russia
| | - Ilda Santos Sanches
- Department of Life Sciences, Centro de Recursos Microbiológicos (CREM) and Research Unit on Applied Molecular Biosciences (UCIBIO, REQUIMTE), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- * E-mail:
| | - Carlos Florindo
- Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Alexander Dmitriev
- Department of Molecular Microbiology, Institute of Experimental Medicine, Saint-Petersburg, Russia
- Department of Fundamental Problems of Medicine and Medical Technologies, Saint-Petersburg State University, Saint-Petersburg, Russia
| |
Collapse
|
37
|
Cozzi R, Malito E, Lazzarin M, Nuccitelli A, Castagnetti A, Bottomley MJ, Margarit I, Maione D, Rinaudo CD. Structure and assembly of group B streptococcus pilus 2b backbone protein. PLoS One 2015; 10:e0125875. [PMID: 25942637 PMCID: PMC4420484 DOI: 10.1371/journal.pone.0125875] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/26/2015] [Indexed: 12/03/2022] Open
Abstract
Group B Streptococcus (GBS) is a major cause of invasive disease in infants. Like other Gram-positive bacteria, GBS uses a sortase C-catalyzed transpeptidation mechanism to generate cell surface pili from backbone and ancillary pilin precursor substrates. The three pilus types identified in GBS contain structural subunits that are highly immunogenic and are promising candidates for the development of a broadly-protective vaccine. Here we report the X-ray crystal structure of the backbone protein of pilus 2b (BP-2b) at 1.06Å resolution. The structure reveals a classical IgG-like fold typical of the pilin subunits of other Gram-positive bacteria. The crystallized portion of the protein (residues 185-468) encompasses domains D2 and D3 that together confer high stability to the protein due to the presence of an internal isopeptide bond within each domain. The D2+D3 region, lacking the N-terminal D1 domain, was as potent as the entire protein in conferring protection against GBS challenge in a well-established mouse model. By site-directed mutagenesis and complementation studies in GBS knock-out strains we identified the residues and motives essential for assembly of the BP-2b monomers into high-molecular weight complexes, thus providing new insights into pilus 2b polymerization.
Collapse
|
38
|
Peng L, Kang S, Yin Z, Jia R, Song X, Li L, Li Z, Zou Y, Liang X, Li L, He C, Ye G, Yin L, Shi F, Lv C, Jing B. Antibacterial activity and mechanism of berberine against Streptococcus agalactiae. Int J Clin Exp Pathol 2015; 8:5217-5223. [PMID: 26191220 PMCID: PMC4503092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 04/26/2015] [Indexed: 06/04/2023]
Abstract
The antibacterial activity and mechanism of berberine against Streptococcus agalactiae were investigated in this study by analyzing the growth, morphology and protein of the S. agalactiae cells treated with berberine. The antibacterial susceptibility test result indicated minimum inhibition concentration (MIC) of berberine against Streptococcus agalactiae was 78 μg/mL and the time-kill curves showed the correlation of concentration-time. After the bacteria was exposed to 78 μg/mL berberine, the fragmentary cell membrane and cells unequal division were observed by the transmission electron microscopy (TEM), indicating the bacterial cells were severely damaged. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) study demonstrated that berberine could damage bacterial cells through destroying cellular proteins. Meanwhile, Fluorescence microscope revealed that berberine could affect the synthesis of DNA. In conclusion, these results strongly suggested that berberine may damage the structure of bacterial cell membrane and inhibit synthesis of protein and DNA, which cause Streptococcus agalactiae bacteria to die eventually.
Collapse
Affiliation(s)
- Lianci Peng
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Shuai Kang
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Zhongqiong Yin
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Renyong Jia
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
- Institute of Prevention Veterinary Medicine, Sichuan Agricultural UniversityChengdu, China
| | - Xu Song
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Li Li
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Zhengwen Li
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Yuanfeng Zou
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Xiaoxia Liang
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Lixia Li
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Changliang He
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Gang Ye
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Lizi Yin
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Fei Shi
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Cheng Lv
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| | - Bo Jing
- College of Veterinary Medicine, Sichuan Agricultural UniversityYa’an, China
| |
Collapse
|
39
|
|
40
|
|
41
|
Huang LY, Wang KY, Xiao D, Chen DF, Geng Y, Wang J, He Y, Wang EL, Huang JL, Xiao GY. Safety and immunogenicity of an oral DNA vaccine encoding Sip of Streptococcus agalactiae from Nile tilapia Oreochromis niloticus delivered by live attenuated Salmonella typhimurium. Fish Shellfish Immunol 2014; 38:34-41. [PMID: 24631734 DOI: 10.1016/j.fsi.2014.02.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/15/2014] [Accepted: 02/20/2014] [Indexed: 06/03/2023]
Abstract
Attenuated Salmonella typhimurium SL7207 was used as a carrier for a reconstructed DNA vaccine against Streptococcus agalactiae. A 1.02 kb DNA fragment, encoding for a portion of the surface immunogenic protein (Sip) of S. agalactiae was inserted into pVAX1. The recombinant plasmid pVAX1-sip was transfected in EPC cells to detect the transient expression by an indirect immunofluorescence assay, together with Western blot analysis. The pVAX1-sip was transformed by electroporation into SL7207. The stability of pVAX1-sip into Salmonella was over 90% after 50 generations with antibiotic selection in vitro while remained stable over 80% during 35 generations under antibiotic-free conditions. The LD50 of SL/pVAX1-sip was 1.7 × 10(11) CFU/fish by intragastric administration which indicated a quite low virulence. Tilapias were inoculated orally at 10(8) CFU/fish, the recombinant bacteria were found present in intestinal tract, spleens and livers and eventually eliminated from the tissues 4 weeks after immunization. Fish immunized at 10(7), 10(8) and 10(9) CFU/fish with different immunization times caused various levels of serum antibody and an effective protection against lethal challenge with the wild-type strain S. agalactiae. Integration studies showed that the pVAX1-sip did not integrate with tilapia chromosomes. The DNA vaccine SL/pVAX1-sip was proved to be safe and effective in protecting tilapias against S. agalactiae infection.
Collapse
Affiliation(s)
- L Y Huang
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - K Y Wang
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China.
| | - D Xiao
- Animal Health Research Institute of Tongwei Co., Ltd., Chengdu, Sichuan 610041, People's Republic of China
| | - D F Chen
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China; Department of Aquaculture, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - Y Geng
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - J Wang
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - Y He
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - E L Wang
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - J L Huang
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| | - G Y Xiao
- Research Center of Fish Disease, Sichuan Agricultural University, Ya'an, Sichuan 625014, People's Republic of China
| |
Collapse
|
42
|
Ragunathan P, Sridaran D, Weigel A, Shabayek S, Spellerberg B, Ponnuraj K. Metal binding is critical for the folding and function of laminin binding protein, Lmb of Streptococcus agalactiae. PLoS One 2013; 8:e67517. [PMID: 23826314 PMCID: PMC3691195 DOI: 10.1371/journal.pone.0067517] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 05/22/2013] [Indexed: 02/03/2023] Open
Abstract
Lmb is a 34 kDa laminin binding surface adhesin of Streptococcus agalactiae. The structure of Lmb reported by us recently has shown that it consists of a metal binding crevice, in which a zinc ion is coordinated to three highly conserved histidines. To elucidate the structural and functional significance of the metal ion in Lmb, these histidines have been mutated to alanine and single, double and triple mutants were generated. These mutations resulted in insolubility of the protein and revealed altered secondary and tertiary structures, as evidenced by circular dichroism and fluorescence spectroscopy studies. The mutations also significantly decreased the binding affinity of Lmb to laminin, implicating the role played by the metal binding residues in maintaining the correct conformation of the protein for its binding to laminin. A highly disordered loop, proposed to be crucial for metal acquisition in homologous structures, was deleted in Lmb by mutation (ΔLmb) and its crystal structure was solved at 2.6 Å. The ΔLmb structure was identical to the native Lmb structure with a bound zinc ion and exhibited laminin binding activity similar to wild type protein, suggesting that the loop might not have an important role in metal acquisition or adhesion in Lmb. Targeted mutations of histidine residues confirmed the importance of the zinc binding crevice for the structure and function of the Lmb adhesin.
Collapse
Affiliation(s)
- Preethi Ragunathan
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
| | - Divya Sridaran
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
| | - Anja Weigel
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
| | - Sarah Shabayek
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University of Ulm, Ulm, Germany
- * E-mail: (BS); (KP)
| | - Karthe Ponnuraj
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
- * E-mail: (BS); (KP)
| |
Collapse
|
43
|
Brega S, Caliot E, Trieu-Cuot P, Dramsi S. SecA localization and SecA-dependent secretion occurs at new division septa in group B Streptococcus. PLoS One 2013; 8:e65832. [PMID: 23762438 PMCID: PMC3676364 DOI: 10.1371/journal.pone.0065832] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/29/2013] [Indexed: 11/19/2022] Open
Abstract
Exported proteins of Streptococcus agalactiae (GBS), which include proteins localized to the bacterial surface or secreted into the extracellular environment, are key players for commensal and pathogenic interactions in the mammalian host. These proteins are transported across the cytoplasmic membrane via the general SecA secretory pathway and those containing the so-called LPXTG sorting motif are covalently attached to the peptidoglycan by sortase A. How SecA, sortase A, and LPXTG proteins are spatially distributed in GBS is not known. In the close relative Streptococcus pyogenes, it was shown that presence of the YSIRKG/S motif (literally YSIRKX3Gx2S) in the signal peptide (SP) constitutes the targeting information for secretion at the septum. Here, using conventional and deconvolution immunofluorescence analyses, we have studied in GBS strain NEM316 the localization of SecA, SrtA, and the secreted protein Bsp whose signal peptide contains a canonical YSIRKG/S motif (YSLRKykfGlaS). Replacing the SP of Bsp with four other SPs containing or not the YSIRKG/S motif did not alter the localized secretion of Bsp at the equatorial ring. Our results indicate that secretion and cell wall-anchoring machineries are localized at the division septum. Cell wall- anchored proteins displayed polar (PilB, Gbs0791), punctuate (CspA) or uniform distribution (Alp2) on the bacterial surface. De novo secretion of Gbs0791 following trypsin treatment indicates that it is secreted at the septum, then redistributed along the lateral sides, and finally accumulated to the poles. We conclude that the ±YSIRK SP rule driving compartimentalized secretion is not true in S. agalactiae.
Collapse
Affiliation(s)
- Sara Brega
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
| | - Elise Caliot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
- * E-mail:
| |
Collapse
|
44
|
Whidbey C, Harrell MI, Burnside K, Ngo L, Becraft AK, Iyer LM, Aravind L, Hitti J, Adams Waldorf KM, Rajagopal L. A hemolytic pigment of Group B Streptococcus allows bacterial penetration of human placenta. J Exp Med 2013; 210:1265-81. [PMID: 23712433 PMCID: PMC3674703 DOI: 10.1084/jem.20122753] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/01/2013] [Indexed: 01/18/2023] Open
Abstract
Microbial infection of the amniotic fluid is a significant cause of fetal injury, preterm birth, and newborn infections. Group B Streptococcus (GBS) is an important human bacterial pathogen associated with preterm birth, fetal injury, and neonatal mortality. Although GBS has been isolated from amniotic fluid of women in preterm labor, mechanisms of in utero infection remain unknown. Previous studies indicated that GBS are unable to invade human amniotic epithelial cells (hAECs), which represent the last barrier to the amniotic cavity and fetus. We show that GBS invades hAECs and strains lacking the hemolysin repressor CovR/S accelerate amniotic barrier failure and penetrate chorioamniotic membranes in a hemolysin-dependent manner. Clinical GBS isolates obtained from women in preterm labor are hyperhemolytic and some are associated with covR/S mutations. We demonstrate for the first time that hemolytic and cytolytic activity of GBS is due to the ornithine rhamnolipid pigment and not due to a pore-forming protein toxin. Our studies emphasize the importance of the hemolytic GBS pigment in ascending infection and fetal injury.
Collapse
Affiliation(s)
- Christopher Whidbey
- Department of Pediatric Infectious Diseases and Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
- Center for Childhood Infections and Prematurity Research, Seattle Children’s Hospital Research Institute, Seattle, WA 98101
- Department of Global Health, University of Washington School of Public Health, Seattle, WA 98195
| | - Maria Isabel Harrell
- Center for Childhood Infections and Prematurity Research, Seattle Children’s Hospital Research Institute, Seattle, WA 98101
| | - Kellie Burnside
- Department of Pediatric Infectious Diseases and Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
| | - Lisa Ngo
- Center for Childhood Infections and Prematurity Research, Seattle Children’s Hospital Research Institute, Seattle, WA 98101
| | - Alexis K. Becraft
- Center for Childhood Infections and Prematurity Research, Seattle Children’s Hospital Research Institute, Seattle, WA 98101
| | - Lakshminarayan M. Iyer
- Computational Biology Branch, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD 20894
| | - L. Aravind
- Computational Biology Branch, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD 20894
| | - Jane Hitti
- Department of Pediatric Infectious Diseases and Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
| | - Kristina M. Adams Waldorf
- Department of Pediatric Infectious Diseases and Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases and Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA 98195
- Center for Childhood Infections and Prematurity Research, Seattle Children’s Hospital Research Institute, Seattle, WA 98101
- Department of Global Health, University of Washington School of Public Health, Seattle, WA 98195
| |
Collapse
|
45
|
Seo HS, Xiong YQ, Sullam PM. Role of the serine-rich surface glycoprotein Srr1 of Streptococcus agalactiae in the pathogenesis of infective endocarditis. PLoS One 2013; 8:e64204. [PMID: 23717569 PMCID: PMC3662765 DOI: 10.1371/journal.pone.0064204] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 04/12/2013] [Indexed: 11/26/2022] Open
Abstract
The binding of bacteria to fibrinogen and platelets are important events in the pathogenesis of infective endocarditis. Srr1 is a serine-rich repeat glycoprotein of Streptococcus agalactiae that binds directly to the Aα chain of human fibrinogen. To assess the impact of Srr1 on the pathogenesis of endocarditis due to S. agalactiae, we first examined the binding of this organism to immobilized human platelets. Strains expressing Srr1 had significantly higher levels of binding to human platelets in vitro, as compared with isogenic Δsrr1 mutants. In addition, platelet binding was inhibited by pretreatment with anti-fibrinogen IgG or purified Srr1 binding region. To assess the contribution of Srr1 to pathogenicity, we compared the relative virulence of S. agalactiae NCTC 10/84 strain and its Δsrr1 mutant in a rat model of endocarditis, where animals were co-infected with the WT and the mutant strains at a 1∶1 ratio. At 72 h post-infection, bacterial densities (CFU/g) of the WT strain within vegetations, kidneys, and spleens were significantly higher, as compared with the Δsrr1 mutant. These results indicate that Srr1 contributes to the pathogenesis of endocarditis due to S. agalactiae, at least in part through its role in fibrinogen-mediated platelet binding.
Collapse
Affiliation(s)
- Ho Seong Seo
- Division of Infectious Diseases, Veterans Affairs Medical Center and the University of California San Francisco, San Francisco, California, United States of America
| | - Yan Q. Xiong
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California, United States of America
- Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Paul M. Sullam
- Division of Infectious Diseases, Veterans Affairs Medical Center and the University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
| |
Collapse
|
46
|
Magalhães V, Andrade EB, Alves J, Ribeiro A, Kim KS, Lima M, Trieu-Cuot P, Ferreira P. Group B Streptococcus hijacks the host plasminogen system to promote brain endothelial cell invasion. PLoS One 2013; 8:e63244. [PMID: 23658816 PMCID: PMC3642152 DOI: 10.1371/journal.pone.0063244] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 03/30/2013] [Indexed: 11/20/2022] Open
Abstract
Group B Streptococcus (GBS) is the leading cause of meningitis in neonates. We have previously shown that plasminogen, once recruited to the GBS cell surface and converted into plasmin by host-derived activators, leads to an enhancement of bacterial virulence. Here, we investigated whether plasmin(ogen) bound at the GBS surface contributes to blood-brain barrier penetration and invasion of the central nervous system. For that purpose, GBS strain NEM316 preincubated with or without plasminogen plus tissue type plasminogen activator was analyzed for the capacity to adhere to, invade and transmigrate the human brain microvascular endothelial cell (hBMEC) monolayer, and to penetrate the central nervous system using a neonatal mouse model. At earlier times of infection, plasmin(ogen)-treated GBS exhibited a significant increase in adherence to and invasion of hBMECs. Later, injury of hBMECs were observed with plasmin(ogen)-treated GBS that displayed a plasmin-like activity. The same results were obtained when hBMECs were incubated with whole human plasma and infected with untreated GBS. To confirm that the observed effects were due to the recruitment and activation of plasminogen on GBS surface, the bacteria were first incubated with epsilon-aminocaproic acid (εACA), an inhibitor of plasminogen binding, and thereafter with plasmin(ogen). A significant decrease in the hBMECs injury that was correlated with a decrease of the GBS surface proteolytic activity was observed. Furthermore, plasmin(ogen)-treated GBS infected more efficiently the brain of neonatal mice than the untreated bacteria, indicating that plasmin(ogen) bound to GBS surface may facilitate the traversal of the blood-brain barrier. A higher survival rate was observed in offspring born from εACA-treated mothers, compared to untreated mice, and no brain infection was detected in these neonates. Our findings suggest that capture of the host plasmin(ogen) by the GBS surface promotes the crossing of the blood-brain barrier and contributes to the establishment of meningitis.
Collapse
Affiliation(s)
- Vanessa Magalhães
- ICBAS- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC- Instituto de Biologia Molecular e Celular, Porto, Portugal
- UFP- Universidade Fernando Pessoa, Faculdade de Ciências da Saúde, Porto, Portugal
| | - Elva Bonifácio Andrade
- ICBAS- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC- Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Joana Alves
- ICBAS- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC- Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Adilia Ribeiro
- ICBAS- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC- Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Kwang Sik Kim
- Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Margarida Lima
- Department of Hematology, Hospital de Santo António (HSA), Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, CNRS ERL3526, Paris, France
| | - Paula Ferreira
- ICBAS- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC- Instituto de Biologia Molecular e Celular, Porto, Portugal
- * E-mail:
| |
Collapse
|
47
|
Firon A, Tazi A, Da Cunha V, Brinster S, Sauvage E, Dramsi S, Golenbock DT, Glaser P, Poyart C, Trieu-Cuot P. The Abi-domain protein Abx1 interacts with the CovS histidine kinase to control virulence gene expression in group B Streptococcus. PLoS Pathog 2013; 9:e1003179. [PMID: 23436996 PMCID: PMC3578759 DOI: 10.1371/journal.ppat.1003179] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 12/19/2012] [Indexed: 12/20/2022] Open
Abstract
Group B Streptococcus (GBS), a common commensal of the female genital tract, is the leading cause of invasive infections in neonates. Expression of major GBS virulence factors, such as the hemolysin operon cyl, is regulated directly at the transcriptional level by the CovSR two-component system. Using a random genetic approach, we identified a multi-spanning transmembrane protein, Abx1, essential for the production of the GBS hemolysin. Despite its similarity to eukaryotic CaaX proteases, the Abx1 function is not involved in a post-translational modification of the GBS hemolysin. Instead, we demonstrate that Abx1 regulates transcription of several virulence genes, including those comprising the hemolysin operon, by a CovSR-dependent mechanism. By combining genetic analyses, transcriptome profiling, and site-directed mutagenesis, we showed that Abx1 is a regulator of the histidine kinase CovS. Overexpression of Abx1 is sufficient to activate virulence gene expression through CovS, overcoming the need for an additional signal. Conversely, the absence of Abx1 has the opposite effect on virulence gene expression consistent with CovS locked in a kinase-competent state. Using a bacterial two-hybrid system, direct interaction between Abx1 and CovS was mapped specifically to CovS domains involved in signal processing. We demonstrate that the CovSR two-component system is the core of a signaling pathway integrating the regulation of CovS by Abx1 in addition to the regulation of CovR by the serine/threonine kinase Stk1. In conclusion, our study reports a regulatory function for Abx1, a member of a large protein family with a characteristic Abi-domain, which forms a signaling complex with the histidine kinase CovS in GBS. The gram-positive Streptococcus genus includes three major human pathogens that are members of the normal microflora: Streptococcus pneumoniae (also known as the pneumococcus), Streptococcus pyogenes (Group A Streptococcus), and Streptococcus agalactiae (Group B Streptococcus). Their carriage in the population is highly dynamic and mostly asymptomatic. However, each of these species can cause a wide spectrum of diseases, from local infections to systemic and fatal infections including septicemia and meningitis. Expression of streptococcal virulence-associated genes is tightly regulated at the transcriptional level. However, the signal(s) and the precise molecular events controlling the switch from commensalism to virulence are not yet understood. In this study, we identified and characterized a bacterial protein essential for virulence gene expression in Group B Streptococcus, the main pathogen of neonates. We show that this transmembrane protein, named Abx1, interacts with the histidine kinase CovS to modulate the activity of the major regulator of virulence CovR. We define how a core set of four proteins, Abx1, CovS, CovR, and the serine/threonine kinase Stk1, interact to control the expression of virulence genes in S. agalactiae. We propose that Abx1-like proteins, that are widespread in bacteria, might be part of a conserved mechanism of two-component system regulation.
Collapse
Affiliation(s)
- Arnaud Firon
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Chuzeville S, Puymège A, Madec JY, Haenni M, Payot S. Characterization of a new CAMP factor carried by an integrative and conjugative element in Streptococcus agalactiae and spreading in Streptococci. PLoS One 2012; 7:e48918. [PMID: 23152820 PMCID: PMC3494709 DOI: 10.1371/journal.pone.0048918] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 10/03/2012] [Indexed: 12/24/2022] Open
Abstract
Genetic exchanges between Streptococci occur frequently and contribute to their genome diversification. Most of sequenced streptococcal genomes carry multiple mobile genetic elements including Integrative and Conjugative Elements (ICEs) that play a major role in these horizontal gene transfers. In addition to genes involved in their mobility and regulation, ICEs also carry genes that can confer selective advantages to bacteria. Numerous elements have been described in S. agalactiae especially those integrated at the 3' end of a tRNA(Lys) encoding gene. In strain 515 of S. agalactiae, an invasive neonate human pathogen, the ICE (called 515_tRNA(Lys)) is functional and carries different putative virulence genes including one encoding a putative new CAMP factor in addition to the one previously described. This work demonstrated the functionality of this CAMP factor (CAMP factor II) in Lactococcus lactis but also in pathogenic strains of veterinary origin. The search for co-hemolytic factors in a collection of field strains revealed their presence in S. uberis, S. dysgalactiae, but also for the first time in S. equisimilis and S. bovis. Sequencing of these genes revealed the prevalence of a species-specific factor in S. uberis strains (Uberis factor) and the presence of a CAMP factor II encoding gene in S. bovis and S. equisimilis. Furthermore, most of the CAMP factor II positive strains also carried an element integrated in the tRNA(Lys) gene. This work thus describes a CAMP factor that is carried by a mobile genetic element and has spread to different streptococcal species.
Collapse
Affiliation(s)
- Sarah Chuzeville
- Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, Lyon, France
- INRA, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- Université de Lorraine, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
| | - Aurore Puymège
- INRA, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- Université de Lorraine, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
| | - Jean-Yves Madec
- Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, Lyon, France
| | - Marisa Haenni
- Unité Antibiorésistance et Virulence Bactériennes, Anses Lyon, Lyon, France
| | - Sophie Payot
- INRA, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- Université de Lorraine, UMR1128 Génétique et Microbiologie, Faculté des Sciences et Technologies, Bd des Aiguillettes BP70239, Vandœuvre-lès-Nancy, France
- * E-mail:
| |
Collapse
|
49
|
Seo HS, Mu R, Kim BJ, Doran KS, Sullam PM. Binding of glycoprotein Srr1 of Streptococcus agalactiae to fibrinogen promotes attachment to brain endothelium and the development of meningitis. PLoS Pathog 2012; 8:e1002947. [PMID: 23055927 PMCID: PMC3464228 DOI: 10.1371/journal.ppat.1002947] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 08/20/2012] [Indexed: 12/11/2022] Open
Abstract
The serine-rich repeat glycoprotein Srr1 of Streptococcus agalactiae (GBS) is thought to be an important adhesin for the pathogenesis of meningitis. Although expression of Srr1 is associated with increased binding to human brain microvascular endothelial cells (hBMEC), the molecular basis for this interaction is not well defined. We now demonstrate that Srr1 contributes to GBS attachment to hBMEC via the direct interaction of its binding region (BR) with human fibrinogen. When assessed by Far Western blotting, Srr1 was the only protein in GBS extracts that bound fibrinogen. Studies using recombinant Srr1-BR and purified fibrinogen in vitro confirmed a direct protein-protein interaction. Srr1-BR binding was localized to amino acids 283–410 of the fibrinogen Aα chain. Structural predictions indicated that the conformation of Srr1-BR is likely to resemble that of SdrG and other related staphylococcal proteins that bind to fibrinogen through a “dock, lock, and latch” mechanism (DLL). Deletion of the predicted latch domain of Srr1-BR abolished the interaction of the BR with fibrinogen. In addition, a mutant GBS strain lacking the latch domain exhibited reduced binding to hBMEC, and was significantly attenuated in an in vivo model of meningitis. These results indicate that Srr1 can bind fibrinogen directly likely through a DLL mechanism, which has not been described for other streptococcal adhesins. This interaction was important for the pathogenesis of GBS central nervous system invasion and subsequent disease progression. Streptococcus agalactiae (Group B streptococcus, GBS) is a leading cause of meningitis in newborns and infants. This life-threatening infection of the brain and surrounding tissues continues to result in a high incidence of morbidity and mortality, despite antibiotic therapy. A key factor in disease production is the ability of this organism to invade the central nervous system, via the bloodstream. We now report that a GBS surface protein called Srr1 binds fibrinogen, a major protein in human blood. This interaction enhances the attachment of GBS to brain vascular endothelial cells, and contributes to the development of meningitis. A mutation in Srr1 that specifically disrupted binding to fibrinogen significantly reduced GBS attachment to brain endothelium, and markedly reduced virulence in an in vivo model of GBS disease. These studies have identified a new mechanism by which Srr1 contributes to GBS invasion of the central nervous system and may provide a basis for novel therapies targeting Srr1 binding.
Collapse
Affiliation(s)
- Ho Seong Seo
- Division of Infectious Diseases, Veterans Affairs Medical Center and the University of California, San Francisco, California, United States of America
| | - Rong Mu
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Brandon J. Kim
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Kelly S. Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
- Department of Pediatrics, University of California at San Diego, School of Medicine, La Jolla, California, United States of America
| | - Paul M. Sullam
- Division of Infectious Diseases, Veterans Affairs Medical Center and the University of California, San Francisco, California, United States of America
- * E-mail:
| |
Collapse
|
50
|
Alkuwaity K, Taylor A, Heckels JE, Doran KS, Christodoulides M. Group B Streptococcus interactions with human meningeal cells and astrocytes in vitro. PLoS One 2012; 7:e42660. [PMID: 22900037 PMCID: PMC3416839 DOI: 10.1371/journal.pone.0042660] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 07/10/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of life-threatening neonatal meningitis and survivors often suffer permanent neurological damage. How this organism interacts with the meninges and subsequently with astrocytes that constitute the underlying cortical glia limitans superficialis is not known. METHODOLOGY/PRINCIPAL FINDINGS In this paper, we demonstrate dose-dependent adherence of GBS over time to human meningioma cells and fetal astrocytes in vitro, which was not influenced by expression of either β-haemolysin/cytolysin (β-h/c) toxin, different capsule serotypes or by absence of capsule (p>0.05). Internalization of GBS by both cell types was, however, a slow and an infrequent event (only 0.02-0.4% of associated bacteria were internalised by 9 h). Expression of β-h/c toxin did not play a role in invasion (p>0.05), whereas capsule expression lead to a reduction (p<0.05) in the numbers of intracellular bacteria recovered. GBS strains induced cytotoxicity as demonstrated by the measurement of lactate dehydrogenase (LDH) enzyme release by 9 h and by viable staining. Increasing levels of meningioma cell death correlated with bacterial growth and the phenotype of β-h/c toxin production, i.e. from weakly, to normo- to hyper-haemolytic. However, cytotoxicity was significantly greater (p<0.05) towards astrocytes, and infection with initial MOI≥0.003 induced 70-100% LDH release. By comparing wild-type (β-h/c(+)) and mutant (ΔcylE β-h/c(-)) strains and β-h/c toxin extracts and by using the surfactant dipalmitoylphosphatidylcholine in cytotoxicity inhibition experiments, β-h/c toxin was demonstrated as principally responsible for cell death. CONCLUSIONS/SIGNIFICANCE This study has described key events in the interactions of GBS with meningeal cells and astrocytes in vitro and a major virulence role for β-h/c toxin. Understanding the mechanisms involved will help to identify potential therapies for improving patient survival and for reducing the incidence and severity of neurological sequelae.
Collapse
Affiliation(s)
- Khalil Alkuwaity
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Alexander Taylor
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - John E. Heckels
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Kelly S. Doran
- Department of Biology, San Diego State University, San Diego, California, United States of America
| | - Myron Christodoulides
- Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
- * E-mail:
| |
Collapse
|