1
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Happonen L, Collin M. Immunomodulating Enzymes from Streptococcus pyogenes-In Pathogenesis, as Biotechnological Tools, and as Biological Drugs. Microorganisms 2024; 12:200. [PMID: 38258026 PMCID: PMC10818452 DOI: 10.3390/microorganisms12010200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
Streptococcus pyogenes, or Group A Streptococcus, is an exclusively human pathogen that causes a wide variety of diseases ranging from mild throat and skin infections to severe invasive disease. The pathogenesis of S. pyogenes infection has been extensively studied, but the pathophysiology, especially of the more severe infections, is still somewhat elusive. One key feature of S. pyogenes is the expression of secreted, surface-associated, and intracellular enzymes that directly or indirectly affect both the innate and adaptive host immune systems. Undoubtedly, S. pyogenes is one of the major bacterial sources for immunomodulating enzymes. Major targets for these enzymes are immunoglobulins that are destroyed or modified through proteolysis or glycan hydrolysis. Furthermore, several enzymes degrade components of the complement system and a group of DNAses degrade host DNA in neutrophil extracellular traps. Additional types of enzymes interfere with cellular inflammatory and innate immunity responses. In this review, we attempt to give a broad overview of the functions of these enzymes and their roles in pathogenesis. For those enzymes where experimentally determined structures exist, the structural aspects of the enzymatic activity are further discussed. Lastly, we also discuss the emerging use of some of the enzymes as biotechnological tools as well as biological drugs and vaccines.
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Affiliation(s)
- Lotta Happonen
- Faculty of Medicine, Department of Clinical Sciences, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden
| | - Mattias Collin
- Faculty of Medicine, Department of Clinical Sciences, Division of Infection Medicine, Lund University, SE-22184 Lund, Sweden
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2
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Wahlenmayer ER, Hammers DE. Streptococcal peptides and their roles in host-microbe interactions. Front Cell Infect Microbiol 2023; 13:1282622. [PMID: 37915845 PMCID: PMC10617681 DOI: 10.3389/fcimb.2023.1282622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
The genus Streptococcus encompasses many bacterial species that are associated with hosts, ranging from asymptomatic colonizers and commensals to pathogens with a significant global health burden. Streptococci produce numerous factors that enable them to occupy their host-associated niches, many of which alter their host environment to the benefit of the bacteria. The ability to manipulate host immune systems to either evade detection and clearance or induce a hyperinflammatory state influences whether bacteria are able to survive and persist in a given environment, while also influencing the propensity of the bacteria to cause disease. Several bacterial factors that contribute to this inter-species interaction have been identified. Recently, small peptides have become increasingly appreciated as factors that contribute to Streptococcal relationships with their hosts. Peptides are utilized by streptococci to modulate their host environment in several ways, including by directly interacting with host factors to disrupt immune system function and signaling to other bacteria to control the expression of genes that contribute to immune modulation. In this review, we discuss the many contributions of Streptococcal peptides in terms of their ability to contribute to pathogenesis and disruption of host immunity. This discussion will highlight the importance of continuing to elucidate the functions of these Streptococcal peptides and pursuing the identification of new peptides that contribute to modulation of host environments. Developing a greater understanding of how bacteria interact with their hosts has the potential to enable the development of techniques to inhibit these peptides as therapeutic approaches against Streptococcal infections.
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Affiliation(s)
| | - Daniel E. Hammers
- Biology Department, Houghton University, Houghton, NY, United States
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3
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Characterization of M-Type-Specific Pilus Expression in Group A Streptococcus. J Bacteriol 2022; 204:e0027022. [PMID: 36286511 PMCID: PMC9664953 DOI: 10.1128/jb.00270-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our ability to characterize how a pathogen infects and causes disease, and consequently our ability to devise approaches to prevent or attenuate such infections, is inhibited by the finding that isolates of a given pathogen often show phenotypic variability, for example, in their ability to adhere to host cells through modulation of cell surface adhesins. Such variability is observed between isolates of group A
Streptococcus
(GAS), and this study investigates the molecular basis for why some GAS isolates produce pili, cell wall-anchored adhesins, in lower abundance than other isolates do.
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4
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Expression of the Group A Streptococcus Fibrinogen-Binding Protein Mrp Is Negatively Regulated by the Small Regulatory RNA FasX. J Bacteriol 2022; 204:e0025122. [PMID: 36286516 PMCID: PMC9664951 DOI: 10.1128/jb.00251-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small regulatory RNAs (sRNAs) represent a major class of regulatory molecule that promotes the ability of the group A
Streptococcus
(GAS) and other pathogens to regulate virulence factor expression. Despite FasX being the best-described sRNA in GAS, there remains much to be learned.
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5
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Bergmann R, Gulotta G, Andreoni F, Sumitomo T, Kawabata S, Zinkernagel AS, Chhatwal GS, Nizet V, Rohde M, Uchiyama S. The group A Streptococcus interleukin-8 protease SpyCEP promotes bacterial intracellular survival by evasion of autophagy. INFECTIOUS MICROBES & DISEASES 2022; 4:116-123. [PMID: 37333426 PMCID: PMC10275413 DOI: 10.1097/im9.0000000000000098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Autophagy serves an innate immune function in defending the host against invading bacteria, including group A Streptococcus (GAS). Autophagy is regulated by numerous host proteins, including the endogenous negative regulator calpain, a cytosolic protease. Globally disseminated serotype M1T1 GAS strains associated with high invasive disease potential express numerous virulence factors and resist autophagic clearance. Upon in vitro infection of human epithelial cell lines with representative wild-type GAS M1T1 strain 5448 (M1.5448), we observed increased calpain activation linked to a specific GAS virulence factor, the IL-8 protease SpyCEP. Calpain activation inhibited autophagy and decreased capture of cytosolic GAS in autophagosomes. In contrast, the serotype M6 GAS strain JRS4 (M6.JRS4), which is highly susceptible to host autophagy-mediated killing, expresses low levels of SpyCEP and does not activate calpain. Overexpression of SpyCEP in M6.JRS4 stimulated calpain activation, inhibited autophagy and significantly decreased bacterial capture in autophagosomes. These paired loss- and gain-of-function studies reveal a novel role for the bacterial protease SpyCEP in enabling GAS M1 evasion of autophagy and host innate immune clearance.
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Affiliation(s)
- René Bergmann
- Central Unit for Microscopy (ZEIM), Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Giuseppe Gulotta
- Central Unit for Microscopy (ZEIM), Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Federica Andreoni
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland
| | - Tomoko Sumitomo
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Shigetada Kawabata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka, Japan
| | - Annelies S. Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland
| | - Gursharan S. Chhatwal
- Central Unit for Microscopy (ZEIM), Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Manfred Rohde
- Central Unit for Microscopy (ZEIM), Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Satoshi Uchiyama
- Central Unit for Microscopy (ZEIM), Helmholtz Centre for Infection Research, Braunschweig, Germany
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
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6
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McKenna S, Huse KK, Giblin S, Pearson M, Majid Al Shibar MS, Sriskandan S, Matthews S, Pease JE. The Role of Streptococcal Cell-Envelope Proteases in Bacterial Evasion of the Innate Immune System. J Innate Immun 2021; 14:69-88. [PMID: 34649250 PMCID: PMC9082167 DOI: 10.1159/000516956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 04/19/2021] [Indexed: 11/19/2022] Open
Abstract
Bacteria possess the ability to evolve varied and ingenious strategies to outwit the host immune system, instigating an evolutionary arms race. Proteases are amongst the many weapons employed by bacteria, which specifically cleave and neutralize key signalling molecules required for a coordinated immune response. In this article, we focus on a family of S8 subtilisin-like serine proteases expressed as cell-envelope proteases (CEPs) by group A and group B streptococci. Two of these proteases known as Streptococcus pyogenes CEP (SpyCEP) and C5a peptidase cleave the chemokine CXCL8 and the complement fragment C5a, respectively. Both CXCL8 and C5a are potent neutrophil-recruiting chemokines, and by neutralizing their activity, streptococci evade a key defence mechanism of innate immunity. We review the mechanisms by which CXCL8 and C5a recruit neutrophils and the characterization of SpyCEP and C5a peptidase, including both in vitro and in vivo studies. Recently described structural insights into the function of this CEP family are also discussed. We conclude by examining the progress of prototypic vaccines incorporating SpyCEP and C5a peptidase in their preparation. Since streptococci-producing SpyCEP and C5a peptidase are responsible for a considerable global disease burden, targeting these proteases by vaccination strategies or by small-molecule antagonists should provide protection from and promote the resolution of streptococcal infections.
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Affiliation(s)
- Sophie McKenna
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Kristin Krohn Huse
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Sean Giblin
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Max Pearson
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | | | - Shiranee Sriskandan
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Stephen Matthews
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - James Edward Pease
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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7
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Abstract
The human skin is our outermost layer and serves as a protective barrier against external insults. Advances in next generation sequencing have enabled the discoveries of a rich and diverse community of microbes - bacteria, fungi and viruses that are residents of this surface. The genomes of these microbes also revealed the presence of many secretory enzymes. In particular, proteases which are hydrolytic enzymes capable of protein cleavage and degradation are of special interest in the skin environment which is enriched in proteins and lipids. In this minireview, we will focus on the roles of these skin-relevant microbial secreted proteases, both in terms of their widely studied roles as pathogenic agents in tissue invasion and host immune inactivation, and their recently discovered roles in inter-microbial interactions and modulation of virulence factors. From these studies, it has become apparent that while microbial proteases are capable of a wide range of functions, their expression is tightly regulated and highly responsive to the environments the microbes are in. With the introduction of new biochemical and bioinformatics tools to study protease functions, it will be important to understand the roles played by skin microbial secretory proteases in cutaneous health, especially the less studied commensal microbes with an emphasis on contextual relevance.
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8
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Hammers D, Carothers K, Lee S. The Role of Bacterial Proteases in Microbe and Host-microbe Interactions. Curr Drug Targets 2021; 23:222-239. [PMID: 34370632 DOI: 10.2174/1389450122666210809094100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Secreted proteases are an important class of factors used by bacterial to modulate their extracellular environment through the cleavage of peptides and proteins. These proteases can range from broad, general proteolytic activity to high degrees of substrate specificity. They are often involved in interactions between bacteria and other species, even across kingdoms, allowing bacteria to survive and compete within their niche. As a result, many bacterial proteases are of clinical importance. The immune system is a common target for these enzymes, and bacteria have evolved ways to use these proteases to alter immune responses for their benefit. In addition to the wide variety of human proteins that can be targeted by bacterial proteases, bacteria also use these secreted factors to disrupt competing microbes, ranging from outright antimicrobial activity to disrupting processes like biofilm formation. OBJECTIVE In this review, we address how bacterial proteases modulate host mechanisms of protection from infection and injury, including immune factors and cell barriers. We also discuss the contributions of bacterial proteases to microbe-microbe interactions, including antimicrobial and anti-biofilm dynamics. CONCLUSION Bacterial secreted proteases represent an incredibly diverse group of factors that bacteria use to shape and thrive in their microenvironment. Due to the range of activities and targets of these proteases, some have been noted for having potential as therapeutics. The vast array of bacterial proteases and their targets remains an expanding field of research, and this field has many important implications for human health.
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Affiliation(s)
- Daniel Hammers
- Department of Biological Sciences, University of Notre Dame, Galvin Hall, Notre Dame, IN 46556, United States
| | - Katelyn Carothers
- Department of Biological Sciences, University of Notre Dame, Galvin Hall, Notre Dame, IN 46556, United States
| | - Shaun Lee
- Department of Biological Sciences, University of Notre Dame, Galvin Hall, Notre Dame, IN 46556, United States
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9
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Jobichen C, Ying Chong T, Hui Ling T, Sivaraman J. The Autocatalytic Cleavage Domain Is Not Required for the Activity of ScpC, a Virulence Protease from Streptococcus pyogenes: A Structural Insight. Biochemistry 2021; 60:1564-1568. [PMID: 33929828 DOI: 10.1021/acs.biochem.1c00185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Group A Streptococcus (GAS, or Streptococcus pyogenes) is a leading human bacterial pathogen with diverse clinical manifestations, ranging from mild to life-threatening and to severe immune sequela. These diseases, combined, account for more than half a million deaths per year, globally. To accomplish its vast pathogenic potential, GAS expresses a multitude of virulent proteins, including the pivotal virulence factor ScpC. ScpC is a narrow-range surface-exposed subtilisin-like serine protease that cleaves the last 14 C-terminal amino acids of interleukin 8 (IL-8 or CXCL8) and impairs essential IL-8 signaling processes. As a result, neutrophil migration, bacterial killing, and the formation of neutrophil extracellular traps are strongly impaired. Also, ScpC has been identified as a potential vaccine candidate. ScpC undergoes an autocatalytic cleavage between Gln244 and Ser245, resulting in two polypeptide chains that assemble together forming the active protease. Previously, we reported that the region harboring the autocatalytic cleavage site, stretching from Gln213 to Asp272, is completely disordered. Here, we show that a deletion mutant (ScpCΔ60) of this region forms a single polypeptide chain, whose crystal structure we determined at 2.9 Å resolution. Moreover, we show that ScpCΔ60 is an active protease capable of cleaving its substrate IL-8 in a manner comparable to that of the wild type. These studies improve our understanding of the proteolytic activity of ScpC.
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Affiliation(s)
- Chacko Jobichen
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Tan Ying Chong
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Tai Hui Ling
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - J Sivaraman
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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10
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Castro SA, Dorfmueller HC. A brief review on Group A Streptococcus pathogenesis and vaccine development. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201991. [PMID: 33959354 PMCID: PMC8074923 DOI: 10.1098/rsos.201991] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is a Gram-positive human-exclusive pathogen, responsible for more than 500 000 deaths annually worldwide. Upon infection, GAS commonly triggers mild symptoms such as pharyngitis, pyoderma and fever. However, recurrent infections or prolonged exposure to GAS might lead to life-threatening conditions. Necrotizing fasciitis, streptococcal toxic shock syndrome and post-immune mediated diseases, such as poststreptococcal glomerulonephritis, acute rheumatic fever and rheumatic heart disease, contribute to very high mortality rates in non-industrialized countries. Though an initial reduction in GAS infections was observed in high-income countries, global outbreaks of GAS, causing rheumatic fever and acute poststreptococcal glomerulonephritis, have been reported over the last decade. At the same time, our understanding of GAS pathogenesis and transmission has vastly increased, with detailed insight into the various stages of infection, beginning with adhesion, colonization and evasion of the host immune system. Despite deeper knowledge of the impact of GAS on the human body, the development of a successful vaccine for prophylaxis of GAS remains outstanding. In this review, we discuss the challenges involved in identifying a universal GAS vaccine and describe several potential vaccine candidates that we believe warrant pursuit.
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Affiliation(s)
- Sowmya Ajay Castro
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Helge C. Dorfmueller
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
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11
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Biswas D, Ambalavanan P, Ravins M, Anand A, Sharma A, Lim KXZ, Tan RYM, Lim HY, Sol A, Bachrach G, Angeli V, Hanski E. LL-37-mediated activation of host receptors is critical for defense against group A streptococcal infection. Cell Rep 2021; 34:108766. [PMID: 33657368 DOI: 10.1016/j.celrep.2021.108766] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 12/03/2020] [Accepted: 01/27/2021] [Indexed: 12/21/2022] Open
Abstract
Group A Streptococcus (GAS) causes diverse human diseases, including life-threatening soft-tissue infections. It is accepted that the human antimicrobial peptide LL-37 protects the host by killing GAS. Here, we show that GAS extracellular protease ScpC N-terminally cleaves LL-37 into two fragments of 8 and 29 amino acids, preserving its bactericidal activity. At sub-bactericidal concentrations, the cleavage inhibits LL-37-mediated neutrophil chemotaxis, shortens neutrophil lifespan, and eliminates P2X7 and EGF receptors' activation. Mutations at the LL-37 cleavage site protect the peptide from ScpC-mediated splitting, maintaining all its functions. The mouse LL-37 ortholog CRAMP is neither cleaved by ScpC nor does it activate P2X7 or EGF receptors. Treating wild-type or CRAMP-null mice with sub-bactericidal concentrations of the non-cleavable LL-37 analogs promotes GAS clearance that is abolished by the administration of either P2X7 or EGF receptor antagonists. We demonstrate that LL-37-mediated activation of host receptors is critical for defense against GAS soft-tissue infections.
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Affiliation(s)
- Debabrata Biswas
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), and Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore.
| | - Poornima Ambalavanan
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), and Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Miriam Ravins
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Aparna Anand
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Abhinay Sharma
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel
| | - Kimberly Xuan Zhen Lim
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), and Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Rachel Ying Min Tan
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), and Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Hwee Ying Lim
- Department of Microbiology and Immunology, National University of Singapore, LSI Immunology Programme, National University of Singapore, Singapore, Singapore
| | - Asaf Sol
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
| | - Gilad Bachrach
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel
| | - Veronique Angeli
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), and Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore; Department of Microbiology and Immunology, National University of Singapore, LSI Immunology Programme, National University of Singapore, Singapore, Singapore
| | - Emanuel Hanski
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), MMID Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), and Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore; Department of Microbiology and Molecular Genetics, The Institute for Medical Research, Israel-Canada (IMRIC), The Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel.
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12
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Siemens N, Snäll J, Svensson M, Norrby-Teglund A. Pathogenic Mechanisms of Streptococcal Necrotizing Soft Tissue Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1294:127-150. [PMID: 33079367 DOI: 10.1007/978-3-030-57616-5_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Necrotizing skin and soft tissue infections (NSTIs) are severe life-threatening and rapidly progressing infections. Beta-hemolytic streptococci, particularly S. pyogenes (group A streptococci (GAS)) but also S. dysgalactiae subsp. equisimilis (SDSE, most group G and C streptococcus), are the main causative agents of monomicrobial NSTIs and certain types, such as emm1 and emm3, are over-represented in NSTI cases. An arsenal of bacterial virulence factors contribute to disease pathogenesis, which is a complex and multifactorial process. In this chapter, we summarize data that have provided mechanistic and immuno-pathologic insight into host-pathogens interactions that contribute to tissue pathology in streptococcal NSTIs. The role of streptococcal surface associated and secreted factors contributing to the hyper-inflammatory state and immune evasion, bacterial load in the tissue and persistence strategies, including intracellular survival and biofilm formation, as well as strategies to mimic NSTIs in vitro are discussed.
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Affiliation(s)
- Nikolai Siemens
- Department of Molecular Genetics and Infection Biology, University of Greifswald, Greifswald, Germany.
| | - Johanna Snäll
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Mattias Svensson
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Anna Norrby-Teglund
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Huddinge, Sweden
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13
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McKenna S, Malito E, Rouse SL, Abate F, Bensi G, Chiarot E, Micoli F, Mancini F, Gomes Moriel D, Grandi G, Mossakowska D, Pearson M, Xu Y, Pease J, Sriskandan S, Margarit I, Bottomley MJ, Matthews S. Structure, dynamics and immunogenicity of a catalytically inactive C XC chemokine-degrading protease SpyCEP from Streptococcus pyogenes. Comput Struct Biotechnol J 2020; 18:650-660. [PMID: 32257048 PMCID: PMC7113628 DOI: 10.1016/j.csbj.2020.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 12/21/2022] Open
Abstract
Over 18 million disease cases and half a million deaths worldwide are estimated to be caused annually by Group A Streptococcus. A vaccine to prevent GAS disease is urgently needed. SpyCEP (Streptococcus pyogenes Cell-Envelope Proteinase) is a surface-exposed serine protease that inactivates chemokines, impairing neutrophil recruitment and bacterial clearance, and has shown promising immunogenicity in preclinical models. Although SpyCEP structure has been partially characterized, a more complete and higher resolution understanding of its antigenic features would be desirable prior to large scale manufacturing. To address these gaps and facilitate development of this globally important vaccine, we performed immunogenicity studies with a safety-engineered SpyCEP mutant, and comprehensively characterized its structure by combining X-ray crystallography, NMR spectroscopy and molecular dynamics simulations. We found that the catalytically-inactive SpyCEP antigen conferred protection similar to wild-type SpyCEP in a mouse infection model. Further, a new higher-resolution crystal structure of the inactive SpyCEP mutant provided new insights into this large chemokine protease comprising nine domains derived from two non-covalently linked fragments. NMR spectroscopy and molecular simulation analyses revealed conformational flexibility that is likely important for optimal substrate recognition and overall function. These combined immunogenicity and structural data demonstrate that the full-length SpyCEP inactive mutant is a strong candidate human vaccine antigen. These findings show how a multi-disciplinary study was used to overcome obstacles in the development of a GAS vaccine, an approach applicable to other future vaccine programs. Moreover, the information provided may also facilitate the structure-based discovery of small-molecule therapeutics targeting SpyCEP protease inhibition.
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Affiliation(s)
- Sophie McKenna
- Department of Life Sciences, Imperial College London, South Kensington Campus, SW7 2AZ, UK
| | - Enrico Malito
- GlaxoSmithKline, 14200 Shady Grove Road, Rockville, MD 20850, United States
| | - Sarah L. Rouse
- Department of Life Sciences, Imperial College London, South Kensington Campus, SW7 2AZ, UK
| | | | | | | | - Francesca Micoli
- GSK Vaccines Institute for Global Health, Via Fiorentina 1, 53100 Siena, Italy
| | - Francesca Mancini
- GSK Vaccines Institute for Global Health, Via Fiorentina 1, 53100 Siena, Italy
| | - Danilo Gomes Moriel
- GSK Vaccines Institute for Global Health, Via Fiorentina 1, 53100 Siena, Italy
| | - Guido Grandi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123 Trento, Italy
| | - Danuta Mossakowska
- Malopolska Centre of Biotechnology (MCB), Jagiellonian University Krakow, Gronostajowa 7a Str, 30-387 Krakow, Poland
| | - Max Pearson
- Department of Infectious Disease, Imperial College London, London W12 0NN, UK
| | - Yingqi Xu
- Department of Life Sciences, Imperial College London, South Kensington Campus, SW7 2AZ, UK
| | - James Pease
- National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK
| | - Shiranee Sriskandan
- Department of Infectious Disease, Imperial College London, London W12 0NN, UK
| | | | | | - Stephen Matthews
- Department of Life Sciences, Imperial College London, South Kensington Campus, SW7 2AZ, UK
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14
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A Multicomponent Vaccine Provides Immunity against Local and Systemic Infections by Group A Streptococcus across Serotypes. mBio 2019; 10:mBio.02600-19. [PMID: 31772056 PMCID: PMC6879722 DOI: 10.1128/mbio.02600-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
GAS is among the most common human pathogens and causes a wide variety of diseases, likely more than any other microorganism. The diverse clinical manifestations of GAS may be attributable to its large repertoire of virulence factors that are selectively and synergistically involved in streptococcal pathogenesis. To date, GAS vaccines have not been successful due to multiple serotypes and postinfection sequelae associated with autoimmunity. In this study, five conserved virulence factors that are involved in GAS pathogenesis were used as a combined vaccine. Intranasal immunization with this vaccine induced humoral and cellular immune responses across GAS serotypes and protected against mucosal, systemic, and skin infections. The significance of this work is to demonstrate that the efficacy of GAS vaccines can be achieved by including multiple nonredundant critical virulence factors and inducing local and systemic immunity. The strategy also provides valuable insights for vaccine development against other pathogens. Group A streptococcus (GAS) species are responsible for a broad spectrum of human diseases, ranging from superficial to invasive infections, and are associated with autoimmune disorders. There is no commercial vaccine against GAS. The clinical manifestations of GAS infection may be attributable to the large repertoire of virulence factors used selectively in different types of GAS disease. Here, we selected five molecules, highly conserved among GAS serotypes, and involved in different pathogenic mechanisms, as a multicomponent vaccine, 5CP. Intranasal (i.n.) immunization with 5CP protected mice against both mucosal and systemic GAS infection across serotypes; the protection lasted at least 6 months. Immunization of mice with 5CP constrained skin lesion development and accelerated lesion recovery. Flow cytometry and enzyme-linked immunosorbent assay analyses revealed that 5CP induced Th17 and antibody responses locally and systemically; however, the Th17 response induced by 5CP resolved more quickly than that to GAS when challenge bacteria were cleared, suggesting that 5CP is less likely to cause autoimmune responses. These findings support that immunization through the i.n. route targeting multiple nonredundant virulence factors can induce immunity against different types of GAS disease and represents an alternative strategy for GAS vaccine development, with favorable efficacy, coverage, duration, and safety.
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Jain I, Danger JL, Burgess C, Uppal T, Sumby P. The group A Streptococcus accessory protein RocA: regulatory activity, interacting partners and influence on disease potential. Mol Microbiol 2019; 113:190-207. [PMID: 31660653 PMCID: PMC7028121 DOI: 10.1111/mmi.14410] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2019] [Indexed: 12/11/2022]
Abstract
The group A Streptococcus (GAS) causes diseases that range from mild (e.g. pharyngitis) to severely invasive (e.g. necrotizing fasciitis). Strain‐ and serotype‐specific differences influence the ability of isolates to cause individual diseases. At the center of this variability is the CovR/S two‐component system and the accessory protein RocA. Through incompletely defined mechanisms, CovR/S and RocA repress the expression of more than a dozen immunomodulatory virulence factors. Alleviation of this repression is selected for during invasive infections, leading to the recovery of covR, covS or rocA mutant strains. Here, we investigated how RocA promotes CovR/S activity, identifying that RocA is a pseudokinase that interacts with CovS. Disruption of CovS kinase or phosphatase activities abolishes RocA function, consistent with RocA acting through the modulation of CovS activity. We also identified, in conflict with a previous study, that the RocA regulon includes the secreted protease‐encoding gene speB. Finally, we discovered an inverse correlation between the virulence of wild‐type, rocA mutant, covS mutant and covR mutant strains during invasive infection and their fitness in an ex vivo upper respiratory tract model. Our data inform on mechanisms that control GAS disease potential and provide an explanation for observed strain‐ and serotype‐specific variability in RocA function.
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Affiliation(s)
- Ira Jain
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Jessica L Danger
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Cameron Burgess
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Timsy Uppal
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
| | - Paul Sumby
- Department of Microbiology & Immunology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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The Role of Streptococcal and Staphylococcal Exotoxins and Proteases in Human Necrotizing Soft Tissue Infections. Toxins (Basel) 2019; 11:toxins11060332. [PMID: 31212697 PMCID: PMC6628391 DOI: 10.3390/toxins11060332] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 12/31/2022] Open
Abstract
Necrotizing soft tissue infections (NSTIs) are critical clinical conditions characterized by extensive necrosis of any layer of the soft tissue and systemic toxicity. Group A streptococci (GAS) and Staphylococcus aureus are two major pathogens associated with monomicrobial NSTIs. In the tissue environment, both Gram-positive bacteria secrete a variety of molecules, including pore-forming exotoxins, superantigens, and proteases with cytolytic and immunomodulatory functions. The present review summarizes the current knowledge about streptococcal and staphylococcal toxins in NSTIs with a special focus on their contribution to disease progression, tissue pathology, and immune evasion strategies.
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17
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Structure of ScpC, a virulence protease from Streptococcus pyogenes, reveals the functional domains and maturation mechanism. Biochem J 2018; 475:2847-2860. [DOI: 10.1042/bcj20180145] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 07/20/2018] [Accepted: 07/25/2018] [Indexed: 12/14/2022]
Abstract
Group A Streptococcus (GAS; Streptococcus pyogenes) causes a wide range of infections, including pharyngitis, impetigo, and necrotizing fasciitis, and results in over half a million deaths annually. GAS ScpC (SpyCEP), a 180-kDa surface-exposed, subtilisin-like serine protease, acts as an essential virulence factor that helps S. pyogenes evade the innate immune response by cleaving and inactivating C-X-C chemokines. ScpC is thus a key candidate for the development of a vaccine against GAS and other pathogenic streptococcal species. Here, we report the crystal structures of full-length ScpC wild-type, the inactive mutant, and the ScpC–AEBSF inhibitor complex. We show ScpC to be a multi-domain, modular protein consisting of nine structural domains, of which the first five constitute the PR + A region required for catalytic activity. The four unique C-terminal domains of this protein are similar to collagen-binding and pilin proteins, suggesting an additional role for ScpC as an adhesin that might mediate the attachment of S. pyogenes to various host tissues. The Cat domain of ScpC is similar to subtilisin-like proteases with significant difference to dictate its specificity toward C-X-C chemokines. We further show that ScpC does not undergo structural rearrangement upon maturation. In the ScpC–inhibitor complex, the bound inhibitor breaks the hydrogen bond between active-site residues, which is essential for catalysis. Guided by our structure, we designed various epitopes and raised antibodies capable of neutralizing ScpC activity. Collectively, our results demonstrate the structure, maturation process, inhibition, and substrate recognition of GAS ScpC, and reveal the presence of functional domains at the C-terminal region.
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Ozberk V, Pandey M, Good MF. Contribution of cryptic epitopes in designing a group A streptococcal vaccine. Hum Vaccin Immunother 2018; 14:2034-2052. [PMID: 29873591 PMCID: PMC6150013 DOI: 10.1080/21645515.2018.1462427] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A successful vaccine needs to target multiple strains of an organism. Streptococcus pyogenes is an organism that utilizes antigenic strain variation as a successful defence mechanism to circumvent the host immune response. Despite numerous efforts, there is currently no vaccine available for this organism. Here we review and discuss the significant obstacles to vaccine development, with a focus on how cryptic epitopes may provide a strategy to circumvent the obstacles of antigenic variation.
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Affiliation(s)
- Victoria Ozberk
- a Griffith University, Institute for Glycomics , Gold Coast Campus, Queensland , Australia
| | - Manisha Pandey
- a Griffith University, Institute for Glycomics , Gold Coast Campus, Queensland , Australia
| | - Michael F Good
- a Griffith University, Institute for Glycomics , Gold Coast Campus, Queensland , Australia
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Soderholm AT, Barnett TC, Korn O, Rivera-Hernandez T, Seymour LM, Schulz BL, Nizet V, Wells CA, Sweet MJ, Walker MJ. Group A Streptococcus M1T1 Intracellular Infection of Primary Tonsil Epithelial Cells Dampens Levels of Secreted IL-8 Through the Action of SpyCEP. Front Cell Infect Microbiol 2018; 8:160. [PMID: 29868516 PMCID: PMC5966554 DOI: 10.3389/fcimb.2018.00160] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/26/2018] [Indexed: 11/22/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus; GAS) commonly causes pharyngitis in children and adults, with severe invasive disease and immune sequelae being an infrequent consequence. The ability of GAS to invade the host and establish infection likely involves subversion of host immune defenses. However, the signaling pathways and innate immune responses of epithelial cells to GAS are not well-understood. In this study, we utilized RNAseq to characterize the inflammatory responses of primary human tonsil epithelial (TEpi) cells to infection with the laboratory-adapted M6 strain JRS4 and the M1T1 clinical isolate 5448. Both strains induced the expression of genes encoding a wide range of inflammatory mediators, including IL-8. Pathway analysis revealed differentially expressed genes between mock and JRS4- or 5448-infected TEpi cells were enriched in transcription factor networks that regulate IL-8 expression, such as AP-1, ATF-2, and NFAT. While JRS4 infection resulted in high levels of secreted IL-8, 5448 infection did not, suggesting that 5448 may post-transcriptionally dampen IL-8 production. Infection with 5448ΔcepA, an isogenic mutant lacking the IL-8 protease SpyCEP, resulted in IL-8 secretion levels comparable to JRS4 infection. Complementation of 5448ΔcepA and JRS4 with a plasmid encoding 5448-derived SpyCEP significantly reduced IL-8 secretion by TEpi cells. Our results suggest that intracellular infection with the pathogenic GAS M1T1 clone induces a strong pro-inflammatory response in primary tonsil epithelial cells, but modulates this host response by selectively degrading the neutrophil-recruiting chemokine IL-8 to benefit infection.
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Affiliation(s)
- Amelia T. Soderholm
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Timothy C. Barnett
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
- Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
| | - Othmar Korn
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia
| | - Tania Rivera-Hernandez
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Lisa M. Seymour
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Benjamin L. Schulz
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
| | - Victor Nizet
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Christine A. Wells
- Centre for Stem Cell Systems, University of Melbourne, Melbourne, VIC, Australia
| | - Matthew J. Sweet
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
- Institute for Molecular Bioscience and IMB Centre for Inflammation and Disease Research, University of Queensland, Brisbane, QLD, Australia
| | - Mark J. Walker
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia
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Multimerization of the Virulence-Enhancing Group A Streptococcus Transcription Factor RivR Is Required for Regulatory Activity. J Bacteriol 2016; 199:JB.00452-16. [PMID: 27795318 DOI: 10.1128/jb.00452-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 10/17/2016] [Indexed: 12/27/2022] Open
Abstract
Group A Streptococcus (GAS) (Streptococcus pyogenes) causes more than 700 million human infections each year. The significant morbidity and mortality rates associated with GAS infections are in part a consequence of the ability of this pathogen to coordinately regulate virulence factor expression during infection. RofA-like protein IV (RivR) is a member of the Mga-like family of transcriptional regulators, and previously we reported that RivR negatively regulates transcription of the hasA and grab virulence factor-encoding genes. Here, we determined that RivR inhibits the ability of GAS to survive and to replicate in human blood. To begin to assess the biochemical basis of RivR activity, we investigated its ability to form multimers, which is a characteristic of Mga-like proteins. We found that RivR forms both dimers and a higher-molecular-mass multimer, which we hypothesize is a tetramer. As cysteine residues are known to contribute to the ability of proteins to dimerize, we created a library of expression plasmids in which each of the four cysteines in RivR was converted to serine. While the C68S RivR protein was essentially unaffected in its ability to dimerize, the C32S and C377S proteins were attenuated, while the C470S protein completely lacked the ability to dimerize. Consistent with dimerization being required for regulatory activity, the C470S RivR protein was unable to repress hasA and grab gene expression in a rivR mutant. Thus, multimer formation is a prerequisite for RivR activity, which supports recent data obtained for other Mga-like family members, suggesting a common regulatory mechanism. IMPORTANCE The modulation of gene transcription is key to the ability of bacterial pathogens to infect hosts to cause disease. Here, we discovered that the group A Streptococcus transcription factor RivR negatively regulates the ability of this pathogen to survive in human blood, and we also began biochemical characterization of this protein. We determined that, in order for RivR to function, it must self-associate, forming both dimers (consisting of two RivR proteins) and higher-order complexes (consisting of more than two RivR proteins). This functional requirement for RivR is shared by other regulators in the same family of proteins, suggesting a common regulatory mechanism. Insight into how these transcription factors function may facilitate the development of novel therapeutic agents targeting their activity.
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Bachert BA, Choi SJ, LaSala PR, Harper TI, McNitt DH, Boehm DT, Caswell CC, Ciborowski P, Keene DR, Flores AR, Musser JM, Squeglia F, Marasco D, Berisio R, Lukomski S. Unique Footprint in the scl1.3 Locus Affects Adhesion and Biofilm Formation of the Invasive M3-Type Group A Streptococcus. Front Cell Infect Microbiol 2016; 6:90. [PMID: 27630827 PMCID: PMC5005324 DOI: 10.3389/fcimb.2016.00090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/15/2016] [Indexed: 12/04/2022] Open
Abstract
The streptococcal collagen-like proteins 1 and 2 (Scl1 and Scl2) are major surface adhesins that are ubiquitous among group A Streptococcus (GAS). Invasive M3-type strains, however, have evolved two unique conserved features in the scl1 locus: (i) an IS1548 element insertion in the scl1 promoter region and (ii) a nonsense mutation within the scl1 coding sequence. The scl1 transcript is drastically reduced in M3-type GAS, contrasting with a high transcription level of scl1 allele in invasive M1-type GAS. This leads to a lack of Scl1 expression in M3 strains. In contrast, while scl2 transcription and Scl2 production are elevated in M3 strains, M1 GAS lack Scl2 surface expression. M3-type strains were shown to have reduced biofilm formation on inanimate surfaces coated with cellular fibronectin and laminin, and in human skin equivalents. Repair of the nonsense mutation and restoration of Scl1 expression on M3-GAS cells, restores biofilm formation on cellular fibronectin and laminin coatings. Inactivation of scl1 in biofilm-capable M28 and M41 strains results in larger skin lesions in a mouse model, indicating that lack of Scl1 adhesin promotes bacterial spread over localized infection. These studies suggest the uniquely evolved scl1 locus in the M3-type strains, which prevents surface expression of the major Scl1 adhesin, contributed to the emergence of the invasive M3-type strains. Furthermore these studies provide insight into the molecular mechanisms mediating colonization, biofilm formation, and pathogenesis of group A streptococci.
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Affiliation(s)
- Beth A Bachert
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Soo J Choi
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Paul R LaSala
- Department of Pathology, West Virginia University Morgantown, WV, USA
| | - Tiffany I Harper
- Department of Pathology, West Virginia University Morgantown, WV, USA
| | - Dudley H McNitt
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Dylan T Boehm
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Clayton C Caswell
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
| | - Pawel Ciborowski
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center Omaha, NE, USA
| | | | - Anthony R Flores
- Section of Infectious Diseases, Department of Pediatrics, Baylor College of Medicine, Texas Children's HospitalHouston, TX, USA; Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute and Hospital SystemHouston, TX, USA
| | - James M Musser
- Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute and Hospital System Houston, TX, USA
| | - Flavia Squeglia
- Institute of Biostructures and Bioimaging, National Research Council Naples, Italy
| | - Daniela Marasco
- Department of Pharmacy, University of Naples Frederico II Naples, Italy
| | - Rita Berisio
- Institute of Biostructures and Bioimaging, National Research Council Naples, Italy
| | - Slawomir Lukomski
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University Morgantown, WV, USA
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Pandey M, Mortensen R, Calcutt A, Powell J, Batzloff MR, Dietrich J, Good MF. Combinatorial Synthetic Peptide Vaccine Strategy Protects against Hypervirulent CovR/S Mutant Streptococci. THE JOURNAL OF IMMUNOLOGY 2016; 196:3364-74. [PMID: 26969753 DOI: 10.4049/jimmunol.1501994] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 02/16/2016] [Indexed: 11/19/2022]
Abstract
Cluster of virulence responder/sensor (CovR/S) mutant group A streptococci (GAS) are serious human pathogens of multiple M protein strains that upregulate expression of virulence factors, including the IL-8 proteaseStreptococcus pyogenescell envelope proteinase (SpyCEP), thus blunting neutrophil-mediated killing and enabling ingress of bacteria from a superficial wound to deep tissue. We previously showed that a combination vaccine incorporating J8-DT (conserved peptide vaccine from the M protein) and a recombinant SpyCEP fragment protects against CovR/S mutants. To enhance the vaccine's safety profile, we identified a minimal epitope (S2) that was the target for anti-SpyCEP Abs that could protect IL-8 from SpyCEP-mediated proteolysis. Abs from healthy humans and from mice experimentally infected with GAS also recognized S2, albeit at low titers. Native SpyCEP may be poorly immunogenic (cryptic or subdominant), and it would be to the organism's advantage if the host did not induce a strong Ab response against it. However, S2 conjugated to diphtheria toxoid is highly immunogenic and induces Abs that recognize and neutralize SpyCEP. Hence, we describe a two-component peptide vaccine that induces Abs (anti-S2) that protect IL-8 from proteolysis and other Abs (anti-J8) that cause strain-independent killing in the presence of neutrophils. We show that either component alone is ineffectual in preventing skin infection and bacteremia due to CovR/S mutants but that the combination induces complete protection. This protection correlated with a significant influx of neutrophils to the infection site. The data strongly suggest that the lack of natural immunity to hypervirulent GAS strains in humans could be rectified by this combination vaccine.
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Affiliation(s)
- Manisha Pandey
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, Queensland 4222, Australia;
| | - Rasmus Mortensen
- Department of Infectious Disease Immunology, Statens Serum Institut, 2300 Copenhagen, Denmark; and Department of Immunology and Microbiology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ainslie Calcutt
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, Queensland 4222, Australia
| | - Jessica Powell
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, Queensland 4222, Australia
| | - Michael R Batzloff
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, Queensland 4222, Australia
| | - Jes Dietrich
- Department of Infectious Disease Immunology, Statens Serum Institut, 2300 Copenhagen, Denmark; and
| | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast Campus, Southport, Queensland 4222, Australia;
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23
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Barnett TC, Cole JN, Rivera-Hernandez T, Henningham A, Paton JC, Nizet V, Walker MJ. Streptococcal toxins: role in pathogenesis and disease. Cell Microbiol 2015; 17:1721-41. [PMID: 26433203 DOI: 10.1111/cmi.12531] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/13/2015] [Accepted: 09/02/2015] [Indexed: 12/15/2022]
Abstract
Group A Streptococcus (Streptococcus pyogenes), group B Streptococcus (Streptococcus agalactiae) and Streptococcus pneumoniae (pneumococcus) are host-adapted bacterial pathogens among the leading infectious causes of human morbidity and mortality. These microbes and related members of the genus Streptococcus produce an array of toxins that act against human cells or tissues, resulting in impaired immune responses and subversion of host physiological processes to benefit the invading microorganism. This toxin repertoire includes haemolysins, proteases, superantigens and other agents that ultimately enhance colonization and survival within the host and promote dissemination of the pathogen.
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Affiliation(s)
- Timothy C Barnett
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Jason N Cole
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.,Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Tania Rivera-Hernandez
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Anna Henningham
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia.,Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Mark J Walker
- Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia
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CovRS-Regulated Transcriptome Analysis of a Hypervirulent M23 Strain of Group A Streptococcus pyogenes Provides New Insights into Virulence Determinants. J Bacteriol 2015. [PMID: 26216843 DOI: 10.1128/jb.00511-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
UNLABELLED The two-component control of virulence (Cov) regulator (R)-sensor (S) (CovRS) regulates the virulence of Streptococcus pyogenes (group A Streptococcus [GAS]). Inactivation of CovS during infection switches the pathogenicity of GAS to a more invasive form by regulating transcription of diverse virulence genes via CovR. However, the manner in which CovRS controls virulence through expression of extended gene families has not been fully determined. In the current study, the CovS-regulated gene expression profiles of a hypervirulent emm23 GAS strain (M23ND/CovS negative [M23ND/CovS(-)]) and a noninvasive isogenic strain (M23ND/CovS(+)), under different growth conditions, were investigated. RNA sequencing identified altered expression of ∼ 349 genes (18% of the chromosome). The data demonstrated that M23ND/CovS(-) achieved hypervirulence by allowing enhanced expression of genes responsible for antiphagocytosis (e.g., hasABC), by abrogating expression of toxin genes (e.g., speB), and by compromising gene products with dispensable functions (e.g., sfb1). Among these genes, several (e.g., parE and parC) were not previously reported to be regulated by CovRS. Furthermore, the study revealed that CovS also modulated the expression of a broad spectrum of metabolic genes that maximized nutrient utilization and energy metabolism during growth and dissemination, where the bacteria encounter large variations in available nutrients, thus restructuring metabolism of GAS for adaption to diverse growth environments. From constructing a genome-scale metabolic model, we identified 16 nonredundant metabolic gene modules that constitute unique nutrient sources. These genes were proposed to be essential for pathogen growth and are likely associated with GAS virulence. The genome-wide prediction of genes associated with virulence identifies new candidate genes that potentially contribute to GAS virulence. IMPORTANCE The CovRS system modulates transcription of ∼ 18% of the genes in the Streptococcus pyogenes genome. Mutations that inactivate CovR or CovS enhance the virulence of this bacterium. We determined complete transcriptomes of a naturally CovS-inactivated invasive deep tissue isolate of an emm23 strain of S. pyogenes (M23ND) and its complemented avirulent variant (CovS(+)). We identified diverse virulence genes whose altered expression revealed a genetic switching of a nonvirulent form of M23ND to a highly virulent strain. Furthermore, we also systematically uncovered for the first time the comparative levels of expression of a broad spectrum of metabolic genes, which reflected different metabolic needs of the bacterium as it invaded deeper tissue of the human host.
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Martin WJ, Steer AC, Smeesters PR, Keeble J, Inouye M, Carapetis J, Wicks IP. Post-infectious group A streptococcal autoimmune syndromes and the heart. Autoimmun Rev 2015; 14:710-25. [PMID: 25891492 DOI: 10.1016/j.autrev.2015.04.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/10/2015] [Indexed: 12/16/2022]
Abstract
There is a pressing need to reduce the high global disease burden of rheumatic heart disease (RHD) and its harbinger, acute rheumatic fever (ARF). ARF is a classical example of an autoimmune syndrome and is of particular immunological interest because it follows a known antecedent infection with group A streptococcus (GAS). However, the poorly understood immunopathology of these post-infectious diseases means that, compared to much progress in other immune-mediated diseases, we still lack useful biomarkers, new therapies or an effective vaccine in ARF and RHD. Here, we summarise recent literature on the complex interaction between GAS and the human host that culminates in ARF and the subsequent development of RHD. We contrast ARF with other post-infectious streptococcal immune syndromes - post-streptococcal glomerulonephritis (PSGN) and the still controversial paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), in order to highlight the potential significance of variations in the host immune response to GAS. We discuss a model for the pathogenesis of ARF and RHD in terms of current immunological concepts and the potential for application of in depth "omics" technologies to these ancient scourges.
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Affiliation(s)
- William John Martin
- Inflammation Division, Water and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia.
| | - Andrew C Steer
- Centre for International Child Health, Department of Pediatrics, University of Melbourne and Murdoch Childrens Research Institute, Parkville, VIC 3052, Australia; Group A Streptococcus Laboratory, Murdoch Childrens Research Institute, Parkville, VIC 3052, Australia
| | - Pierre Robert Smeesters
- Centre for International Child Health, Department of Pediatrics, University of Melbourne and Murdoch Childrens Research Institute, Parkville, VIC 3052, Australia; Group A Streptococcus Laboratory, Murdoch Childrens Research Institute, Parkville, VIC 3052, Australia
| | - Joanne Keeble
- Inflammation Division, Water and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Michael Inouye
- Medical Systems Biology, Department of Pathology and Department of Microbiology and Immunology, University of Melbourne, VIC 3010, Australia
| | | | - Ian P Wicks
- Inflammation Division, Water and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia; Rheumatology Unit, Royal Melbourne Hospital, Parkville, VIC 3052, Australia.
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Sanson M, O'Neill BE, Kachroo P, Anderson JR, Flores AR, Valson C, Cantu CC, Makthal N, Karmonik C, Fittipaldi N, Kumaraswami M, Musser JM, Olsen RJ. A naturally occurring single amino acid replacement in multiple gene regulator of group A Streptococcus significantly increases virulence. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:462-71. [PMID: 25476528 DOI: 10.1016/j.ajpath.2014.10.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/03/2014] [Accepted: 10/14/2014] [Indexed: 12/27/2022]
Abstract
Single-nucleotide polymorphisms (SNPs) are the most common source of genetic variation within a species; however, few investigations demonstrate how naturally occurring SNPs may increase strain virulence. We recently used group A Streptococcus as a model pathogen to study bacteria strain genotype-patient disease phenotype relationships. Whole-genome sequencing of approximately 800 serotype M59 group A Streptococcus strains, recovered during an outbreak of severe invasive infections across North America, identified a disproportionate number of SNPs in the gene encoding multiple gene regulator of group A Streptococcus (mga). Herein, we report results of studies designed to test the hypothesis that the most commonly occurring SNP, encoding a replacement of arginine for histidine at codon 201 of Mga (H201R), significantly increases virulence. Whole transcriptome analysis revealed that the H201R replacement significantly increased expression of mga and 54 other genes, including many proven virulence factors. Compared to the wild-type strain, a H201R isogenic mutant strain caused significantly larger skin lesions in mice. Serial quantitative bacterial culture and noninvasive magnetic resonance imaging also demonstrated that the isogenic H201R strain was significantly more virulent in a nonhuman primate model of joint infection. These findings show that the H201R replacement in Mga increases the virulence of M59 group A Streptococcus and provide new insight to how a naturally occurring SNP in bacteria contributes to human disease phenotypes.
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Affiliation(s)
- Misu Sanson
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas; School of Biotechnology, School of Medicine and Health Sciences, Tecnológico de Monterrey, Monterrey, Mexico
| | - Brian E O'Neill
- Department of Translational Imaging, MRI Core, Houston Methodist Research Institute, Houston, Texas
| | - Priyanka Kachroo
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas
| | - Jeff R Anderson
- Department of Translational Imaging, MRI Core, Houston Methodist Research Institute, Houston, Texas
| | - Anthony R Flores
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas; Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas
| | - Chandni Valson
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas
| | - Concepcion C Cantu
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas
| | - Nishanth Makthal
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas
| | - Christof Karmonik
- Department of Translational Imaging, MRI Core, Houston Methodist Research Institute, Houston, Texas
| | - Nahuel Fittipaldi
- Department of Laboratory Medicine and Pathobiology, Public Health Ontario, University of Toronto, Toronto, Ontario, Canada
| | - Muthiah Kumaraswami
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas
| | - James M Musser
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas
| | - Randall J Olsen
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Center for Molecular and Translational Human Infectious Diseases Research, Houston, Texas.
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Clinical laboratory response to a mock outbreak of invasive bacterial infections: a preparedness study. J Clin Microbiol 2014; 52:4210-6. [PMID: 25253790 DOI: 10.1128/jcm.02164-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Large hospital-based clinical laboratories must be prepared to rapidly investigate potential infectious disease outbreaks. To challenge the ability of our molecular diagnostics laboratory to use whole-genome sequencing in a potential outbreak scenario and identify impediments to these efforts, we studied 84 invasive serotype emm59 group A streptococcus (GAS) strains collected in the United States. We performed a rapid-response exercise to the mock outbreak scenario using whole-genome sequencing, genome-wide transcript analysis, and mouse virulence studies. The protocol changes installed in response to the lessons learned were tested in a second iteration. The initial investigation was completed in 9 days. Whole-genome sequencing showed that the invasive infections were caused by multiple subclones of epidemic emm59 GAS strains likely spread to the United States from Canada. The phylogenetic tree showed a strong temporal-spatial structure with diversity in mobile genetic element content, features that are useful for identifying closely related strains and possible transmission events. The genome data informed the epidemiology, identifying multiple patients who likely acquired the organisms through direct person-to-person transmission. Transcriptome analysis unexpectedly revealed significantly altered expression of genes encoding a two-component regulator and the hyaluronic acid capsule virulence factor. Mouse infection studies confirmed a high-virulence capacity of these emm59 organisms. Whole-genome sequencing, coupled with transcriptome analysis and animal virulence studies, can be rapidly performed in a clinical environment to effectively contribute to patient care decisions and public health maneuvers.
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28
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Jimenez JC, Federle MJ. Quorum sensing in group A Streptococcus. Front Cell Infect Microbiol 2014; 4:127. [PMID: 25309879 PMCID: PMC4162386 DOI: 10.3389/fcimb.2014.00127] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/26/2014] [Indexed: 01/05/2023] Open
Abstract
Quorum sensing (QS) is a widespread phenomenon in the microbial world that has important implications in the coordination of population-wide responses in several bacterial pathogens. In Group A Streptococcus (GAS), many questions surrounding QS systems remain to be solved pertaining to their function and their contribution to the GAS lifestyle in the host. The QS systems of GAS described to date can be categorized into four groups: regulator gene of glucosyltransferase (Rgg), Sil, lantibiotic systems, and LuxS/AI-2. The Rgg family of proteins, a conserved group of transcription factors that modify their activity in response to signaling peptides, has been shown to regulate genes involved in virulence, biofilm formation and competence. The sil locus, whose expression is regulated by the activity of signaling peptides and a putative two-component system (TCS), has been implicated on regulating genes involved with invasive disease in GAS isolates. Lantibiotic regulatory systems are involved in the production of bacteriocins and their autoregulation, and some of these genes have been shown to target both bacterial organisms as well as processes of survival inside the infected host. Finally AI-2 (dihydroxy pentanedione, DPD), synthesized by the LuxS enzyme in several bacteria including GAS, has been proposed to be a universal bacterial communication molecule. In this review we discuss the mechanisms of these four systems, the putative functions of their targets, and pose critical questions for future studies.
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Affiliation(s)
- Juan Cristobal Jimenez
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago Chicago, IL, USA
| | - Michael J Federle
- Department of Medicinal Chemistry and Pharmacognosy, Center for Pharmaceutical Biotechnology, College of Pharmacy, University of Illinois at Chicago Chicago, IL, USA
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Andreoni F, Ogawa T, Ogawa M, Madon J, Uchiyama S, Schuepbach RA, Zinkernagel AS. The IL-8 protease SpyCEP is detrimental for Group A Streptococcus host-cells interaction and biofilm formation. Front Microbiol 2014; 5:339. [PMID: 25071751 PMCID: PMC4090674 DOI: 10.3389/fmicb.2014.00339] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/18/2014] [Indexed: 12/20/2022] Open
Abstract
SpyCEP-mediated chemokine degradation translates into more efficient spreading and increased severity of invasive Group A Streptococcus (GAS) infections, due to impaired neutrophil recruitment to the site of infection. SpyCEP is markedly up-regulated in invasive as compared to colonizing GAS isolates raising the question whether SpyCEP expression hinders bacterial attachment and thus colonization of the host. To address this question we used a molecular approach involving the use of homologous GAS strains either expressing or not SpyCEP or expressing an enzymatically inactive variant of SpyCEP. We found that expression of enzymatically functional SpyCEP lowered GAS adherence and invasion potential toward various epithelial and endothelial cells. SpyCEP also blunted biofilm formation capacity. Our data indicate that expression of SpyCEP decreases colonization and thus might be detrimental for the spreading of GAS.
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Affiliation(s)
- Federica Andreoni
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich Zurich, Switzerland
| | - Taiji Ogawa
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich Zurich, Switzerland
| | - Mariko Ogawa
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich Zurich, Switzerland
| | - Jerzy Madon
- Surgical Intensive Care Medicine, University Hospital Zurich, University of Zurich Zurich, Switzerland
| | - Satoshi Uchiyama
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich Zurich, Switzerland
| | - Reto A Schuepbach
- Surgical Intensive Care Medicine, University Hospital Zurich, University of Zurich Zurich, Switzerland
| | - Annelies S Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich Zurich, Switzerland
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Dual-site phosphorylation of the control of virulence regulator impacts group a streptococcal global gene expression and pathogenesis. PLoS Pathog 2014; 10:e1004088. [PMID: 24788524 PMCID: PMC4006921 DOI: 10.1371/journal.ppat.1004088] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 03/10/2014] [Indexed: 11/20/2022] Open
Abstract
Phosphorylation relays are a major mechanism by which bacteria alter transcription in response to environmental signals, but understanding of the functional consequences of bacterial response regulator phosphorylation is limited. We sought to characterize how phosphorylation of the control of virulence regulator (CovR) protein from the major human pathogen group A Streptococcus (GAS) influences GAS global gene expression and pathogenesis. CovR mainly serves to repress GAS virulence factor-encoding genes and has been shown to homodimerize following phosphorylation on aspartate-53 (D53) in vitro. We discovered that CovR is phosphorylated in vivo and that such phosphorylation is partially heat-stable, suggesting additional phosphorylation at non-aspartate residues. Using mass spectroscopy along with targeted mutagenesis, we identified threonine-65 (T65) as an additional CovR phosphorylation site under control of the serine/threonine kinase (Stk). Phosphorylation on T65, as mimicked by the recombinant CovR T65E variant, abolished in vitro CovR D53 phosphorylation. Similarly, isoallelic GAS strains that were either unable to be phosphorylated at D53 (CovR-D53A) or had functional constitutive phosphorylation at T65 (CovR-T65E) had essentially an identical gene repression profile to each other and to a CovR-inactivated strain. However, the CovR-D53A and CovR-T65E isoallelic strains retained the ability to positively influence gene expression that was abolished in the CovR-inactivated strain. Consistent with these observations, the CovR-D53A and CovR-T65E strains were hypervirulent compared to the CovR-inactivated strain in a mouse model of invasive GAS disease. Surprisingly, an isoalleic strain unable to be phosphorylated at CovR T65 (CovR-T65A) was hypervirulent compared to the wild-type strain, as auto-regulation of covR gene expression resulted in lower covR gene transcript and CovR protein levels in the CovR-T65A strain. Taken together, these data establish that CovR is phosphorylated in vivo and elucidate how the complex interplay between CovR D53 activating phosphorylation, T65 inhibiting phosphorylation, and auto-regulation impacts streptococcal host-pathogen interaction. Group A Streptococcus (GAS) causes a variety of human diseases ranging from mild throat infections to deadly invasive infections. The capacity of GAS to cause infections at such diverse locations is dependent on its ability to precisely control the production of a broad variety of virulence factors. The control of virulence regulator (CovR) is a master regulator of GAS genes encoding virulence factors. It is known that CovR can be phosphorylated on aspartate-53 in vitro and that such phosphorylation increases its regulatory activity, but what additional factors influence CovR-mediated gene expression have not been established. Herein we show for the first time that CovR is phosphorylated in vivo and that phosphorylation of CovR on threonine-65 by the threonine/serine kinase Stk prevents aspartate-53 phosphorylation, thereby decreasing CovR regulatory activity. Further, while CovR-mediated gene repression is highly dependent on aspartate-53 phosphorylation, CovR-mediated gene activation proceeds via a phosphorylation-independent mechanism. Modifications in CovR phosphorylation sites significantly affected the expression of GAS virulence factors during infection and markedly altered the ability of GAS to cause disease in mice. These data establish that multiple inter-related pathways converge to influence CovR phosphorylation, thereby providing new insight into the complex regulatory network used by GAS during infection.
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31
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Neutrophils select hypervirulent CovRS mutants of M1T1 group A Streptococcus during subcutaneous infection of mice. Infect Immun 2014; 82:1579-90. [PMID: 24452689 DOI: 10.1128/iai.01458-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogen mutants arise during infections. Mechanisms of selection for pathogen variants are poorly understood. We tested whether neutrophils select mutations in the two-component regulatory system CovRS of group A Streptococcus (GAS) during infection using the lack of production of the protease SpeB (SpeB activity negative [SpeB(A-)]) as a marker. Depletion of neutrophils by antibodies RB6-8C5 and 1A8 reduced the percentage of SpeB(A-) variants (SpeB(A-)%) recovered from mice infected with GAS strain MGAS2221 by >76%. Neutrophil recruitment and SpeB(A-)% among recovered GAS were reduced by 95% and 92%, respectively, in subcutaneous MGAS2221 infection of CXCR2(-/-) mice compared with control mice. In air sac infection with MGAS2221, levels of neutrophils and macrophages in lavage fluid were reduced by 49% and increased by 287%, respectively, in CXCR2(-/-) mice compared with control mice, implying that macrophages play an insignificant role in the reduction of selection for SpeB(A-) variants in CXCR2(-/-) mice. One randomly chosen SpeB(A-) mutant outcompeted MGAS2221 in normal mice but was outcompeted by MGAS2221 in neutropenic mice and had enhancements in expression of virulence factors, innate immune evasion, skin invasion, and virulence. This and nine other SpeB(A-) variants from a mouse all had nonsynonymous covRS mutations that resulted in the SpeB(A-) phenotype and enhanced expression of the CovRS-controlled secreted streptococcal esterase (SsE). Our findings are consistent with a model that neutrophils select spontaneous covRS mutations that maximize the potential of GAS to evade neutrophil responses, resulting in variants with enhanced survival and virulence. To our knowledge, this is the first report of the critical contribution of neutrophils to the selection of pathogen variants.
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32
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Lynskey NN, Goulding D, Gierula M, Turner CE, Dougan G, Edwards RJ, Sriskandan S. RocA truncation underpins hyper-encapsulation, carriage longevity and transmissibility of serotype M18 group A streptococci. PLoS Pathog 2013; 9:e1003842. [PMID: 24367267 PMCID: PMC3868526 DOI: 10.1371/journal.ppat.1003842] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 11/04/2013] [Indexed: 12/03/2022] Open
Abstract
Group A streptococcal isolates of serotype M18 are historically associated with epidemic waves of pharyngitis and the non-suppurative immune sequela rheumatic fever. The serotype is defined by a unique, highly encapsulated phenotype, yet the molecular basis for this unusual colony morphology is unknown. Here we identify a truncation in the regulatory protein RocA, unique to and conserved within our serotype M18 GAS collection, and demonstrate that it underlies the characteristic M18 capsule phenotype. Reciprocal allelic exchange mutagenesis of rocA between M18 GAS and M89 GAS demonstrated that truncation of RocA was both necessary and sufficient for hyper-encapsulation via up-regulation of both precursors required for hyaluronic acid synthesis. Although RocA was shown to positively enhance covR transcription, quantitative proteomics revealed RocA to be a metabolic regulator with activity beyond the CovR/S regulon. M18 GAS demonstrated a uniquely protuberant chain formation following culture on agar that was dependent on excess capsule and the RocA mutation. Correction of the M18 rocA mutation reduced GAS survival in human blood, and in vivo naso-pharyngeal carriage longevity in a murine model, with an associated drop in bacterial airborne transmission during infection. In summary, a naturally occurring truncation in a regulator explains the encapsulation phenotype, carriage longevity and transmissibility of M18 GAS, highlighting the close interrelation of metabolism, capsule and virulence. Group A streptococcus is an important human pathogen which produces a polysaccharide capsule that confers resistance to killing by white blood cells and allows bacterial adherence to host epithelial surfaces. Serotype M18 isolates over-produce capsule, creating a unique and characteristic appearance when grown on blood agar. This feature may underlie the waves of infectious pharyngitis and subsequent onset of rheumatic fever associated with this serotype. The reason for hyper-encapsulation of M18 GAS is unknown. Here we show that a naturally-occurring truncation in an important regulatory protein, RocA, underlies serotype M18 hyper-encapsulation. By correcting the truncation we were able to reverse hyper-encapsulation, modify the 3-D structural morphology of bacteria within colonies and alter the overall protein expression pattern of the bacterium. We were able to reproduce characteristics of M18 streptococci in a different serotype strain by introducing the same truncation mutation. It was also possible to show that the truncation in RocA led to prolonged nasopharyngeal carriage of GAS in mice and also promoted bacterial airborne transmission. Thus, the propensity for M18 isolates to be associated with outbreaks of pharyngitis and rheumatic fever may be accounted for by the level of encapsulation induced by truncation of the regulatory protein RocA.
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Affiliation(s)
- Nicola N. Lynskey
- Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - David Goulding
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Magdalena Gierula
- Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Claire E. Turner
- Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Robert J. Edwards
- Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Shiranee Sriskandan
- Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, United Kingdom
- * E-mail:
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33
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Cook LC, Federle MJ. Peptide pheromone signaling in Streptococcus and Enterococcus. FEMS Microbiol Rev 2013; 38:473-92. [PMID: 24118108 DOI: 10.1111/1574-6976.12046] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/06/2013] [Accepted: 09/09/2013] [Indexed: 01/08/2023] Open
Abstract
Intercellular chemical signaling in bacteria, commonly referred to as quorum sensing (QS), relies on the production and detection of compounds known as pheromones to elicit coordinated responses among members of a community. Pheromones produced by Gram-positive bacteria are comprised of small peptides. Based on both peptide structure and sensory system architectures, Gram-positive bacterial signaling pathways may be classified into one of four groups with a defining hallmark: cyclical peptides of the Agr type, peptides that contain Gly-Gly processing motifs, sensory systems of the RNPP family, or the recently characterized Rgg-like regulatory family. The recent discovery that Rgg family members respond to peptide pheromones increases substantially the number of species in which QS is likely a key regulatory component. These pathways control a variety of fundamental behaviors including conjugation, natural competence for transformation, biofilm development, and virulence factor regulation. Overlapping QS pathways found in multiple species and pathways that utilize conserved peptide pheromones provide opportunities for interspecies communication. Here we review pheromone signaling identified in the genera Enterococcus and Streptococcus, providing examples of all four types of pathways.
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Affiliation(s)
- Laura C Cook
- Department of Medicinal Chemistry and Pharmacognosy, Center for Pharmaceutical Biotechnology, University of Illinois at Chicago, Chicago, IL, USA
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34
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Association between polymorphisms in the csrRS two-component regulatory system and invasive group A streptococcal infection. Eur J Clin Microbiol Infect Dis 2013; 33:735-43. [DOI: 10.1007/s10096-013-2005-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/16/2013] [Indexed: 11/26/2022]
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Characterization of streptococcal platelet-activating factor acetylhydrolase variants that are involved in innate immune evasion. Infect Immun 2013; 81:3128-38. [PMID: 23774595 DOI: 10.1128/iai.00398-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human pathogen group A streptococcus (GAS) has developed mechanisms to subvert innate immunity. We recently reported that the secreted esterase produced by serotype M1 GAS (SsE(M1)) reduces neutrophil recruitment by targeting platelet-activating factor (PAF). SsE(M1) and SsE produced by serotype M28 GAS (SsE(M28)) have a 37% sequence difference. This study aims at determining whether SsE(M28) is also a PAF acetylhydrolase and participates in innate immune evasion. We also examined whether SsE evolved to target PAF by characterizing the PAF acetylhydrolase (PAF-AH) activity and substrate specificity of SsE(M1), SsE(M28), SeE, the SsE homologue in Streptococcus equi, and human plasma PAF-AH (hpPAF-AH). PAF incubated with SsE(M28) or SeE was converted into lyso-PAF. SsE(M1) and SsE(M28) had kcat values of 373 s(-1) and 467 s(-1), respectively, that were ≥ 30-fold greater than that of hpPAF-AH (12 s(-1)). The comparison of SsE(M1), SsE(M28), and hpPAF-AH in kcat and Km in hydrolyzing triglycerides, acetyl esters, and PAF indicates that the SsE proteins are more potent hydrolases against PAF and have high affinity for PAF. SsE(M28) possesses much lower esterase activities against triglycerides and other esters than SsE(M1) but have similar potency with SsE(M1) in PAF hydrolysis. Deletion of sse(M28) in a covS deletion mutant of GAS increased neutrophil recruitment and reduced skin infection, whereas in trans expression of SsE(M28) in GAS reduced neutrophil infiltration and increased skin invasion in subcutaneous infection of mice. These results suggest that the SsE proteins evolved to target PAF for enhancing innate immune evasion and skin invasion.
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Regulation of inhibition of neutrophil infiltration by the two-component regulatory system CovRS in subcutaneous murine infection with group A streptococcus. Infect Immun 2013; 81:974-83. [PMID: 23319556 DOI: 10.1128/iai.01218-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Hypervirulent invasive group A streptococcus (GAS) isolates inhibit neutrophil infiltration more than pharyngitis isolates do, and the molecular basis of this difference is not well understood. This study was designed to first determine whether natural null mutation of the two-component regulatory system CovRS is responsible for the enhancement of the inhibition of neutrophil recruitment seen in hypervirulent GAS. Next, we examined the role of CovRS-regulated interleukin-8/CXC chemokine peptidase (SpyCEP), C5a peptidase (ScpA), and platelet-activating factor acetylhydrolase (SsE) in the enhanced innate immune evasion. Invasive isolate MGAS5005 induces less neutrophil infiltration and produced a greater lesion area than pharyngitis isolate MGAS2221 in subcutaneous infections of mice. It is known that MGAS5005, but not MGAS2221, has a natural 1-bp deletion in the covS gene. Replacement of covS(Δ1bp) in MGAS5005 with wild-type covS resulted in the MGAS2221 phenotype. Deletion of covS from MGAS2221 resulted in the MGAS5005 phenotype. Tests of single, double, and triple deletion mutants of the MGAS5005 sse, spyCEP, and scpA genes found that SsE plays a more important role than SpyCEP and ScpA in the inhibition of neutrophil recruitment and that SsE, SpyCEP, and ScpA do not have synergistic effects on innate immune evasion by MGAS5005. Deletion of sse, but not spyCEP or scpA, of MGAS2221 enhances neutrophil recruitment. Thus, covS null mutations can cause substantial inhibition of neutrophil recruitment by enhancing the expression of the chemoattractant-degrading virulence factors, and SsE, but not SpyCEP or ScpA, is required for CovRS-regulated GAS inhibition of neutrophil infiltration.
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Abstract
Bacterial pathogens rely on proteolysis for variety of purposes during the infection process. In the cytosol, the main proteolytic players are the conserved Clp and Lon proteases that directly contribute to virulence through the timely degradation of virulence regulators and indirectly by providing tolerance to adverse conditions such as those experienced in the host. In the membrane, HtrA performs similar functions whereas the extracellular proteases, in close contact with host components, pave the way for spreading infections by degrading host matrix components or interfering with host cell signalling to short-circuit host cell processes. Common to both intra- and extracellular proteases is the tight control of their proteolytic activities. In general, substrate recognition by the intracellular proteases is highly selective which is, in part, attributed to the chaperone activity associated with the proteases either encoded within the same polypeptide or on separate subunits. In contrast, substrate recognition by extracellular proteases is less selective and therefore these enzymes are generally expressed as zymogens to prevent premature proteolytic activity that would be detrimental to the cell. These extracellular proteases are activated in complex cascades involving auto-processing and proteolytic maturation. Thus, proteolysis has been adopted by bacterial pathogens at multiple levels to ensure the success of the pathogen in contact with the human host.
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Affiliation(s)
- Dorte Frees
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Stigbøjlen 4, Frederiksberg, C 1870, Denmark
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38
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Vitamin D and the human antimicrobial peptide LL-37 enhance group a streptococcus resistance to killing by human cells. mBio 2012; 3:mBio.00394-12. [PMID: 23093388 PMCID: PMC3482505 DOI: 10.1128/mbio.00394-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The CsrRS two-component regulatory system of group A Streptococcus (GAS; Streptococcus pyogenes) responds to subinhibitory concentrations of the human antimicrobial peptide LL-37. LL-37 signaling through CsrRS results in upregulation of genes that direct synthesis of virulence factors, including the hyaluronic acid capsule and streptolysin O (SLO). Here, we demonstrate that a consequence of this response is augmented GAS resistance to killing by human oropharyngeal keratinocytes, neutrophils, and macrophages. LL-37-induced upregulation of SLO and hyaluronic acid capsule significantly reduced internalization of GAS by keratinocytes and phagocytic killing by neutrophils and macrophages. Because vitamin D induces LL-37 production by macrophages, we tested its effect on macrophage killing of GAS. In contrast to the reported enhancement of macrophage function in relation to other pathogens, treatment of macrophages with 1α,25-dihydroxy-vitamin D3 paradoxically reduced the ability of macrophages to control GAS infection. These observations demonstrate that LL-37 signals through CsrRS to induce a virulence phenotype in GAS characterized by heightened resistance to ingestion and killing by both epithelial cells and phagocytes. By inducing LL-37 production in macrophages, vitamin D may contribute to this paradoxical exacerbation of GAS infection. IMPORTANCE It remains poorly understood why group A Streptococcus (GAS) causes asymptomatic colonization or localized throat inflammation in most individuals but rarely progresses to invasive infection. The human antimicrobial peptide LL-37, which is produced as part of the innate immune response to GAS infection, signals through the GAS CsrRS two-component regulatory system to upregulate expression of multiple virulence factors. This study reports that two CsrRS-regulated GAS virulence factors-streptolysin O and the hyaluronic acid capsule-are critical in LL-37-induced resistance of GAS to killing by human throat epithelial cells and by neutrophils and macrophages. Vitamin D, which increases LL-37 production in macrophages, has the paradoxical effect of increasing GAS resistance to macrophage-mediated killing. In this way, the human innate immune response may promote the transition from GAS colonization to invasive infection.
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Streptococcus pyogenes SpyCEP influences host-pathogen interactions during infection in a murine air pouch model. PLoS One 2012; 7:e40411. [PMID: 22848376 PMCID: PMC3407228 DOI: 10.1371/journal.pone.0040411] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/06/2012] [Indexed: 01/21/2023] Open
Abstract
Streptococcus pyogenes is a major human pathogen worldwide, responsible for both local and systemic infections. These bacteria express the subtilisin-like protease SpyCEP which cleaves human IL-8 and related chemokines. We show that localization of SpyCEP is growth-phase and strain dependent. Significant shedding was observed only in a strain naturally overexpressing SpyCEP, and shedding was not dependent on SpyCEP autoproteolytic activity. Surface-bound SpyCEP in two different strains was capable of cleaving IL-8. To investigate SpyCEP action in vivo, we adapted the mouse air pouch model of infection for parallel quantification of bacterial growth, host immune cell recruitment and chemokine levels in situ. In response to infection, the predominant cells recruited were neutrophils, monocytes and eosinophils. Concomitantly, the chemokines KC, LIX, and MIP-2 in situ were drastically increased in mice infected with the SpyCEP knockout strain, and growth of this mutant strain was reduced compared to the wild type. SpyCEP has been described as a potential vaccine candidate against S. pyogenes, and we showed that surface-associated SpyCEP was recognized by specific antibodies. In vitro, such antibodies also counteracted the inhibitory effects of SpyCEP on chemokine mediated PMN recruitment. Thus, α-SpyCEP antibodies may benefit the host both directly by enabling opsonophagocytosis, and indirectly, by neutralizing an important virulence factor. The animal model we employed shows promise for broad application in the study of bacterial pathogenesis.
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Bensi G, Mora M, Tuscano G, Biagini M, Chiarot E, Bombaci M, Capo S, Falugi F, Manetti AGO, Donato P, Swennen E, Gallotta M, Garibaldi M, Pinto V, Chiappini N, Musser JM, Janulczyk R, Mariani M, Scarselli M, Telford JL, Grifantini R, Norais N, Margarit I, Grandi G. Multi high-throughput approach for highly selective identification of vaccine candidates: the Group A Streptococcus case. Mol Cell Proteomics 2012; 11:M111.015693. [PMID: 22286755 PMCID: PMC3433891 DOI: 10.1074/mcp.m111.015693] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 01/05/2012] [Indexed: 11/23/2022] Open
Abstract
We propose an experimental strategy for highly accurate selection of candidates for bacterial vaccines without using in vitro and/or in vivo protection assays. Starting from the observation that efficacious vaccines are constituted by conserved, surface-associated and/or secreted components, the strategy contemplates the parallel application of three high throughput technologies, i.e. mass spectrometry-based proteomics, protein array, and flow-cytometry analysis, to identify this category of proteins, and is based on the assumption that the antigens identified by all three technologies are the protective ones. When we tested this strategy for Group A Streptococcus, we selected a total of 40 proteins, of which only six identified by all three approaches. When the 40 proteins were tested in a mouse model, only six were found to be protective and five of these belonged to the group of antigens in common to the three technologies. Finally, a combination of three protective antigens conferred broad protection against a panel of four different Group A Streptococcus strains. This approach may find general application as an accelerated and highly accurate path to bacterial vaccine discovery.
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Affiliation(s)
- Giuliano Bensi
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Marirosa Mora
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Giovanna Tuscano
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Massimiliano Biagini
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Emiliano Chiarot
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Mauro Bombaci
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Sabrina Capo
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Fabiana Falugi
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Andrea G. O. Manetti
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Paolo Donato
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Erwin Swennen
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Marilena Gallotta
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Manuela Garibaldi
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Vittoria Pinto
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Nico Chiappini
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - James M. Musser
- §Center for Molecular and Translational Human Infectious Diseases Research, The Methodist Hospital Research Institute, Houston, Texas 77030
| | - Robert Janulczyk
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Massimo Mariani
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Maria Scarselli
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - John L. Telford
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Renata Grifantini
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Nathalie Norais
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Immaculada Margarit
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
| | - Guido Grandi
- From the ‡Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100, Siena, Italy
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Liu M, Zhu H, Li J, Garcia CC, Feng W, Kirpotina LN, Hilmer J, Tavares LP, Layton AW, Quinn MT, Bothner B, Teixeira MM, Lei B. Group A Streptococcus secreted esterase hydrolyzes platelet-activating factor to impede neutrophil recruitment and facilitate innate immune evasion. PLoS Pathog 2012; 8:e1002624. [PMID: 22496650 PMCID: PMC3320582 DOI: 10.1371/journal.ppat.1002624] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/21/2012] [Indexed: 11/19/2022] Open
Abstract
The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a null covS mutation enhances neutrophil ingress to infection sites in the skin of mice. In trans expression of SsE in MGAS2221 reduces neutrophil recruitment and enhances skin invasion. The sse deletion mutant of MGAS5005 (ΔsseMGAS5005) is more efficiently cleared from skin than the parent strain. SsE hydrolyzes the sn-2 ester bond of platelet-activating factor (PAF), converting biologically active PAF into inactive lyso-PAF. KM and kcat of SsE for hydrolysis of 2-thio-PAF were similar to those of the human plasma PAF acetylhydrolase. Treatment of PAF with SsE abolishes the capacity of PAF to induce activation and chemotaxis of human neutrophils. More importantly, PAF receptor-deficient mice significantly reduce neutrophil infiltration to the site of ΔsseMGAS5005 infection. These findings identify the first secreted PAF acetylhydrolase of bacterial pathogens and support a novel GAS evasion mechanism that reduces phagocyte recruitment to sites of infection by inactivating PAF, providing a new paradigm for bacterial evasion of neutrophil responses. GAS is a major human pathogen causing a variety of infections, including pharyngitis and necrotizing fasciitis. GAS pathogenesis is mediated by a large array of secreted and cell-surface virulence factors. However, the functions of many GAS virulence factors are poorly understood. Recently, we reported that the esterase secreted by GAS (SsE) is a CovRS (the control of virulence two component regulatory system)-regulated protective antigen and is critical for spreading in the skin and systemic dissemination of GAS in a mouse model of necrotizing fasciitis. This report presents three major findings regarding the function and functional mechanism of SsE: 1) SsE contributes to GAS inhibition of neutrophil recruitment; 2) SsE is a potent PAF acetylhydrolase and the first secreted bacterial PAF acetylhydrolase identified so far; and 3) the PAF receptor significantly contributes to neutrophil recruitment in skin GAS infection. These findings support a novel mechanism for evasion of the innate immune system by GAS that may be relevant to other infections.
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Affiliation(s)
- Mengyao Liu
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Hui Zhu
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- Department of Physiology, Harbin Medical University, Harbin, People's Republic of China
| | - Jinquan Li
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Cristiana C. Garcia
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Wenchao Feng
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Liliya N. Kirpotina
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Jonathan Hilmer
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Luciana P. Tavares
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Arthur W. Layton
- Montana Veterinary Diagnostic Laboratory, Bozeman, Montana, United States of America
| | - Mark T. Quinn
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, United States of America
| | - Mauro M. Teixeira
- Laboratory of Immunopharmacology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Benfang Lei
- Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- * E-mail:
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Full-genome dissection of an epidemic of severe invasive disease caused by a hypervirulent, recently emerged clone of group A Streptococcus. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1522-34. [PMID: 22330677 DOI: 10.1016/j.ajpath.2011.12.037] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 11/06/2011] [Accepted: 12/02/2011] [Indexed: 11/23/2022]
Abstract
Group A Streptococcus (GAS) causes an exceptionally broad range of infections in humans, from relatively mild pharyngitis and skin infections to life-threatening necrotizing fasciitis and toxic shock syndrome. An epidemic of severe invasive human infections caused by type emm59 GAS, heretofore an exceedingly rare cause of disease, spread west to east across Canada over a 3-year period (2006 to 2008). By sequencing the genomes of 601 epidemic, historic, and other emm59 organisms, we discovered that a recently emerged, genetically distinct emm59 clone is responsible for the Canadian epidemic. Using near-real-time genome sequencing, we were able to show spread of the Canadian epidemic clone into the United States. The extensive genome data permitted us to identify patterns of geographic dissemination as well as links between emm59 subclonal lineages that cause infections. Mouse and nonhuman primate models of infection demonstrated that the emerged clone is unusually virulent. Transmission of epidemic emm59 strains may have occurred primarily by skin contact, as suggested by an experimental model of skin transmission. In addition, the emm59 strains had a significantly impaired ability to persist in human saliva and to colonize the oropharynx of mice, and seldom caused human pharyngitis. Our study contributes new information to the rapidly emerging field of molecular pathogenomics of bacterial epidemics and illustrates how full-genome data can be used to precisely illuminate the landscape of strain dissemination during a bacterial epidemic.
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Molloy EM, Cotter PD, Hill C, Mitchell DA, Ross RP. Streptolysin S-like virulence factors: the continuing sagA. Nat Rev Microbiol 2011; 9:670-81. [PMID: 21822292 DOI: 10.1038/nrmicro2624] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Streptolysin S (SLS) is a potent cytolytic toxin and virulence factor that is produced by nearly all Streptococcus pyogenes strains. Despite a 100-year history of research on this toxin, it has only recently been established that SLS is just one of an extended family of post-translationally modified virulence factors (the SLS-like peptides) that are produced by some streptococci and other Gram-positive pathogens, such as Listeria monocytogenes and Clostridium botulinum. In this Review, we describe the identification, genetics, biochemistry and various functions of SLS. We also discuss the shared features of the virulence-associated SLS-like peptides, as well as their place within the rapidly expanding family of thiazole/oxazole-modified microcins (TOMMs).
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Affiliation(s)
- Evelyn M Molloy
- Department of Microbiology, University College Cork, Cork, Ireland
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Olsen RJ, Watkins ME, Cantu CC, Beres SB, Musser JM. Virulence of serotype M3 Group A Streptococcus strains in wax worms (Galleria mellonella larvae). Virulence 2011; 2:111-9. [PMID: 21258213 DOI: 10.4161/viru.2.2.14338] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Group A Streptococcus (GAS) causes human infections that range in severity from pharyngitis ("strep-throat") to necrotizing fasciitis ("flesh-eating disease"). To facilitate investigation of the molecular basis of host-pathogen interactions, infection models capable of rapidly screening for differences in GAS strain virulence are needed. To this end, we developed a Galleria mellonella larvae (wax worm) model of invasive GAS infection and used it to compare the virulence of serotype M3 GAS strains. We found that GAS causes severe tissue damage and kills wax worms in a dose-dependent manner. The virulence of genetically distinct GAS strains was compared by Kaplan-Meier survival analysis and determining 50% lethal doses (LD 50). Host-pathogen interactions were further characterized using quantitative culture, histopathology and TaqMan assays. GAS strains known to be highly pathogenic in mice and monkeys caused significantly lower survival and had significantly lower LD 50s in wax worms than GAS strains associated with attenuated virulence or asymptomatic carriage. Furthermore, isogenic inactivation of proven virulence factors resulted in a significantly increased LD 50 and decreased lesion size compared to the wild-type strain, a finding that also strongly correlates with animal studies. Importantly, survival analysis and LD 50 determination in wax worms supported our hypothesis that a newly emerged GAS subclone that is epidemiologically associated with more human necrotizing fasciitis cases than its progenitor lineage has significantly increased virulence. We conclude that GAS virulence in wax worms strongly correlates with the data obtained in vertebrate models, and thus, the Galleria mellonella larva is a useful host organism to study GAS pathogenesis.
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Affiliation(s)
- Randall J Olsen
- The Methodist Hospital Research Institute, Houston, TX, USA.
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45
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Bonifait L, Grenier D. The SspA subtilisin-like protease of Streptococcus suis triggers a pro-inflammatory response in macrophages through a non-proteolytic mechanism. BMC Microbiol 2011; 11:47. [PMID: 21362190 PMCID: PMC3058005 DOI: 10.1186/1471-2180-11-47] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 03/01/2011] [Indexed: 02/05/2023] Open
Abstract
Background Streptococcus suis is a major swine pathogen worldwide that causes meningitis, septicemia, arthritis, and endocarditis. Using animal models, a surface-associated subtilisin-like protease (SspA) has recently been shown to be an important virulence factor for S. suis. In this study, we hypothesized that the S. suis SspA subtilisin-like protease may modulate cytokine secretion by macrophages thus contributing to the pathogenic process of meningitis. Results Phorbol 12-myristate 13-acetate-differentiated U937 macrophages were stimulated with recombinant SspA prior to monitor cytokine secretion by ELISA. Our results indicated that the recombinant SspA was able to dose-dependently induce IL-1β, IL-6, TNF-α, CXCL8 and CCL5 secretion in macrophages. The heat-inactivated protease was still able to induce cytokine secretion suggesting a non-proteolytic mechanism of macrophage activation. Using specific kinase inhibitors, evidence were bought that cytokine secretion by macrophages stimulated with the recombinant SspA involves the mitogen-activated protein kinase signal transduction pathway. While stimulation of macrophages with low concentrations of recombinant SspA was associated to secretion of high amounts of CCL5, the use of recombinant SspA at a high concentration resulted in low amounts of CCL5 detected in the conditioned medium. This was found to be associated with a proteolytic degradation of CCL5 by SspA. The ability of SspA to induce cytokine secretion in macrophages was confirmed using a mutant of S. suis deficient in SspA expression. Conclusion In conclusion, this study identified a new mechanism by which the S. suis SspA may promote central nervous system inflammation associated with meningitis.
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Affiliation(s)
- Laetitia Bonifait
- Groupe de Recherche en Écologie Buccale, Faculté de médecine dentaire, Université Laval, Quebec City, Quebec, Canada
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Olsen RJ, Ashraf M, Gonulal VE, Ayeras AA, Cantu C, Shea PR, Carroll RK, Humbird T, Greaver JL, Swain JL, Chang E, Ragasa W, Jenkins L, Lally KP, Blasdel T, Cagle P, Musser JM. Lower respiratory tract infection in cynomolgus macaques (Macaca fascicularis) infected with group A Streptococcus. Microb Pathog 2010; 49:336-47. [DOI: 10.1016/j.micpath.2010.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 06/28/2010] [Accepted: 06/30/2010] [Indexed: 10/19/2022]
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Kaur SJ, Nerlich A, Bergmann S, Rohde M, Fulde M, Zähner D, Hanski E, Zinkernagel A, Nizet V, Chhatwal GS, Talay SR. The CXC chemokine-degrading protease SpyCep of Streptococcus pyogenes promotes its uptake into endothelial cells. J Biol Chem 2010; 285:27798-805. [PMID: 20562101 DOI: 10.1074/jbc.m109.098053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Streptococcus pyogenes expresses the LPXTG motif-containing cell envelope serine protease SpyCep (also called ScpC, PrtS) that degrades and inactivates the major chemoattractant interleukin 8 (IL-8), thereby impairing host neutrophil recruitment. In this study, we identified a novel function of SpyCep: the ability to mediate uptake into primary human endothelial cells. SpyCep triggered its uptake into endothelial cells but not into human epithelial cells originating from pharynx or lung, indicating an endothelial cell-specific uptake mechanism. SpyCep mediated cellular invasion by an endosomal/lysosomal pathway distinct from the caveolae-mediated invasion pathway of S. pyogenes. Recombinant expression and purification of proteolytically active SpyCep and a series of subfragments allowed functional dissection of the domains responsible for endothelial cell invasion and IL-8 degradation. The N-terminal PR domain was sufficient to mediate endothelial cell invasion, whereas for IL-8-degrading activity, the protease domain and the flanking A domain were required. A polyclonal rabbit serum raised against the recombinant protease efficiently blocked the invasion-mediating activity of SpyCep but not its proteolytic function, further indicating that SpyCep-mediated internalization is independent from its enzymatic activity. SpyCep may thus specifically mediate its own uptake as secreted protein into human endothelial cells.
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Affiliation(s)
- Simran Jeet Kaur
- Department of Microbial Pathogenesis, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany
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Kurupati P, Turner CE, Tziona I, Lawrenson RA, Alam FM, Nohadani M, Stamp GW, Zinkernagel AS, Nizet V, Edwards RJ, Sriskandan S. Chemokine-cleaving Streptococcus pyogenes protease SpyCEP is necessary and sufficient for bacterial dissemination within soft tissues and the respiratory tract. Mol Microbiol 2010; 76:1387-97. [PMID: 20158613 PMCID: PMC2904501 DOI: 10.1111/j.1365-2958.2010.07065.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2010] [Indexed: 01/04/2023]
Abstract
SpyCEP is a Streptococcus pyogenes protease that cleaves CXCL8/IL-8 and its activity is associated with human invasive disease severity. We investigated the role of SpyCEP in S. pyogenes necrotizing fasciitis and respiratory tract infection in mice using isogenic strains differing only in SpyCEP expression. SpyCEP cleaved human CXCL1, 2, 6 and 8 plus murine CXCL1 and 2 at a structurally conserved site. Mice were infected in thigh muscle with a strain of S. pyogenes that expresses a high level of SpyCEP, or with an isogenic non-SpyCEP expressing strain. SpyCEP expression by S. pyogenes hindered bacterial clearance from muscle, and enhanced bacterial spread, associated with cleavage of murine chemoattractant CXCL1. Mice were then infected with Lactococcus lactis strains that differed only in SpyCEP expression. In contrast to the parent L. lactis strain (lacks SpyCEP), which was avirulent when administered intramuscularly, infection with a strain that expressed SpyCEP heterologously led to dramatic systemic illness within 24 h, failure to clear bacteria from muscle and marked dissemination to other organs. In the upper airways, SpyCEP expression was required for survival of L. lactis but not S. pyogenes. However, dissemination of S. pyogenes to the lung was SpyCEP-dependent and was associated with evidence of chemokine cleavage. Taken together, the studies provide clear evidence that SpyCEP is necessary and sufficient for systemic bacterial dissemination from a soft tissue focus in this model and also underlies dissemination in the respiratory tract.
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Affiliation(s)
- Prathiba Kurupati
- Department of Infectious Diseases and Immunity, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Claire E Turner
- Department of Infectious Diseases and Immunity, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Ioanna Tziona
- Department of Infectious Diseases and Immunity, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Richard A Lawrenson
- Department of Infectious Diseases and Immunity, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Faraz M Alam
- Department of Infectious Diseases and Immunity, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Mahrokh Nohadani
- Histopathology Department, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Gordon W Stamp
- Histopathology Department, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | | | - Victor Nizet
- Department of Pediatrics, University of California at San DiegoLa Jolla, CA 92093, USA
| | - Robert J Edwards
- Department of Experimental Medicine and Toxicology, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
| | - Shiranee Sriskandan
- Department of Infectious Diseases and Immunity, Imperial College London, Hammersmith HospitalDu Cane Road, London W12 0NN, UK
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Bestebroer J, de Haas CJ, van Strijp JA. How microorganisms avoid phagocyte attraction. FEMS Microbiol Rev 2010; 34:395-414. [DOI: 10.1111/j.1574-6976.2009.00202.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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50
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Zingaretti C, Falugi F, Nardi‐Dei V, Pietrocola G, Mariani M, Liberatori1 Marilena Gallotta S, Tontini M, Tani C, Speziale P, Grandi G, Margarit I. Streptococcus pyogenes
SpyCEP: a chemokine‐inactivating protease with unique structural and biochemical features. FASEB J 2010; 24:2839-48. [DOI: 10.1096/fj.09-145631] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Chiara Zingaretti
- Novartis Vaccines & Diagnostics Siena Italy
- Istituto Nazionale di Genetica Molecolare Milan Italy
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