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Lê-Bury P, Echenique-Rivera H, Pizarro-Cerdá J, Dussurget O. Determinants of bacterial survival and proliferation in blood. FEMS Microbiol Rev 2024; 48:fuae013. [PMID: 38734892 PMCID: PMC11163986 DOI: 10.1093/femsre/fuae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 04/29/2024] [Accepted: 05/10/2024] [Indexed: 05/13/2024] Open
Abstract
Bloodstream infection is a major public health concern associated with high mortality and high healthcare costs worldwide. Bacteremia can trigger fatal sepsis whose prevention, diagnosis, and management have been recognized as a global health priority by the World Health Organization. Additionally, infection control is increasingly threatened by antimicrobial resistance, which is the focus of global action plans in the framework of a One Health response. In-depth knowledge of the infection process is needed to develop efficient preventive and therapeutic measures. The pathogenesis of bloodstream infection is a dynamic process resulting from the invasion of the vascular system by bacteria, which finely regulate their metabolic pathways and virulence factors to overcome the blood immune defenses and proliferate. In this review, we highlight our current understanding of determinants of bacterial survival and proliferation in the bloodstream and discuss their interactions with the molecular and cellular components of blood.
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Affiliation(s)
- Pierre Lê-Bury
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Autoimmune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT), 18 route du Panorama, 92260 Fontenay-aux-Roses, France
| | - Hebert Echenique-Rivera
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
| | - Javier Pizarro-Cerdá
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, Yersinia National Reference Laboratory, WHO Collaborating Research & Reference Centre for Plague FRA-146, 28 rue du Dr Roux, 75015 Paris, France
| | - Olivier Dussurget
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
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2
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Hastings CJ, Syed SS, Marques CNH. Subversion of the Complement System by Pseudomonas aeruginosa. J Bacteriol 2023; 205:e0001823. [PMID: 37436150 PMCID: PMC10464199 DOI: 10.1128/jb.00018-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen heavily implicated in chronic diseases. Immunocompromised patients that become infected with P. aeruginosa usually are afflicted with a lifelong chronic infection, leading to worsened patient outcomes. The complement system is an integral piece of the first line of defense against invading microorganisms. Gram-negative bacteria are thought to be generally susceptible to attack from complement; however, P. aeruginosa can be an exception, with certain strains being serum resistant. Various molecular mechanisms have been described that confer P. aeruginosa unique resistance to numerous aspects of the complement response. In this review, we summarize the current published literature regarding the interactions of P. aeruginosa and complement, as well as the mechanisms used by P. aeruginosa to exploit various complement deficiencies and the strategies used to disrupt or hijack normal complement activities.
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Affiliation(s)
- Cody James Hastings
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Shazrah Salim Syed
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Cláudia Nogueira Hora Marques
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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3
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Arredondo-Alonso S, Blundell-Hunter G, Fu Z, Gladstone RA, Fillol-Salom A, Loraine J, Cloutman-Green E, Johnsen PJ, Samuelsen Ø, Pöntinen AK, Cléon F, Chavez-Bueno S, De la Cruz MA, Ares MA, Vongsouvath M, Chmielarczyk A, Horner C, Klein N, McNally A, Reis JN, Penadés JR, Thomson NR, Corander J, Taylor PW, McCarthy AJ. Evolutionary and functional history of the Escherichia coli K1 capsule. Nat Commun 2023; 14:3294. [PMID: 37322051 PMCID: PMC10272209 DOI: 10.1038/s41467-023-39052-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 05/26/2023] [Indexed: 06/17/2023] Open
Abstract
Escherichia coli is a leading cause of invasive bacterial infections in humans. Capsule polysaccharide has an important role in bacterial pathogenesis, and the K1 capsule has been firmly established as one of the most potent capsule types in E. coli through its association with severe infections. However, little is known about its distribution, evolution and functions across the E. coli phylogeny, which is fundamental to elucidating its role in the expansion of successful lineages. Using systematic surveys of invasive E. coli isolates, we show that the K1-cps locus is present in a quarter of bloodstream infection isolates and has emerged in at least four different extraintestinal pathogenic E. coli (ExPEC) phylogroups independently in the last 500 years. Phenotypic assessment demonstrates that K1 capsule synthesis enhances E. coli survival in human serum independent of genetic background, and that therapeutic targeting of the K1 capsule re-sensitizes E. coli from distinct genetic backgrounds to human serum. Our study highlights that assessing the evolutionary and functional properties of bacterial virulence factors at population levels is important to better monitor and predict the emergence of virulent clones, and to also inform therapies and preventive medicine to effectively control bacterial infections whilst significantly lowering antibiotic usage.
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Affiliation(s)
- Sergio Arredondo-Alonso
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
| | | | - Zuyi Fu
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | - Rebecca A Gladstone
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
| | - Alfred Fillol-Salom
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | | | - Elaine Cloutman-Green
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Anna K Pöntinen
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - François Cléon
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Susana Chavez-Bueno
- University of Missouri Kansas City, Kansas City, USA
- Division of Infectious Diseases, Children's Mercy Hospital Kansas City, UMKC School of Medicine, Kansas City, USA
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Mexico City, Mexico
- Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Agnieszka Chmielarczyk
- Faculty of Medicine, Chair of Microbiology, Jagiellonian University Medical College, Czysta str. 18, 31-121, Kraków, Poland
| | - Carolyne Horner
- British Society for Antimicrobial Chemotherapy, Birmingham, UK
| | - Nigel Klein
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Joice N Reis
- Laboratory of Pathology and Molecular Biology (LPBM), Gonçalo Moniz Research Institute, Oswaldo Cruz Foundation, Salvador, Brazil
- Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Brazil
| | - José R Penadés
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | - Nicholas R Thomson
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Jukka Corander
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway.
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK.
- Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland.
| | - Peter W Taylor
- School of Pharmacy, University College London, London, UK.
| | - Alex J McCarthy
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK.
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4
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Hastings CJ, Himmler GE, Patel A, Marques CNH. Immune Response Modulation by Pseudomonas aeruginosa Persister Cells. mBio 2023; 14:e0005623. [PMID: 36920189 PMCID: PMC10128020 DOI: 10.1128/mbio.00056-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Bacterial persister cells-a metabolically dormant subpopulation tolerant to antimicrobials-contribute to chronic infections and are thought to evade host immunity. In this work, we studied the ability of Pseudomonas aeruginosa persister cells to withstand host innate immunity. We found that persister cells resist MAC-mediated killing by the complement system despite being bound by complement protein C3b at levels similar to regular vegetative cells, in part due to reduced bound C5b, and are engulfed at a lower rate (10- to 100-fold), even following opsonization. Once engulfed, persister cells resist killing and, contrary to regular vegetative cells which induce a M1 favored (CD80+/CD86+/CD206-, high levels of CXCL-8, IL-6, and TNF-α) macrophage polarization, they initially induce a M2 favored macrophage polarization (CD80+/CD86+/CD206+, high levels of IL-10, and intermediate levels of CXCL-8, IL-6, and TNF-α), which is skewed toward M1 favored polarization (high levels of CXCL-8 and IL-6, lower levels of IL-10) by 24 h of infection, once persister cells awaken. Overall, our findings further establish the ability of persister cells to evade the innate host response and to contribute chronic infections. IMPORTANCE Bacterial cells have a subpopulation-persister cells-that have a low metabolism. Persister cells survive antimicrobial treatment and can regrow to cause chronic and recurrent infections. Currently little is known as to whether the human immune system recognizes and responds to the presence of persister cells. In this work, we studied the ability of persister cells from Pseudomonas aeruginosa to resist the host defense system (innate immunity). We found that this subpopulation is recognized by the defense system, but it is not killed. The lack of killing likely stems from hindering the immune response regulation, resulting in a failure to distinguish whether a pathogen is present. Findings from this work increase the overall knowledge as to how chronic infections are resilient.
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Affiliation(s)
- Cody James Hastings
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Grace Elizabeth Himmler
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Arpeet Patel
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Cláudia Nogueira Hora Marques
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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5
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Hastings CJ, Himmler GE, Patel A, Marques CNH. Immune response modulation by Pseudomonas aeruginosa persister cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.07.523056. [PMID: 36711557 PMCID: PMC9881899 DOI: 10.1101/2023.01.07.523056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Bacterial persister cells - a metabolically dormant subpopulation tolerant to antimicrobials - contribute to chronic infections and are thought to evade host immunity. In this work, we studied the ability of Pseudomonas aeruginosa persister cells to withstand host innate immunity. We found that persister cells resist MAC-mediated killing by the complement system despite being bound by complement protein C3b at levels similar to regular vegetative cells, in part due to reduced bound C5b - and are engulfed at a lower rate (10-100 fold), even following opsonization. Once engulfed, persister cells resist killing and, contrary to regular vegetative cells which induce a M1 favored (CD80+/CD86+/CD206-, high levels of CXCL-8, IL-6, and TNF-α) macrophage polarization, they initially induce a M2 favored macrophage polarization (CD80+/CD86+/CD206+, high levels of IL-10, and intermediate levels of CXCL-8, IL-6, and TNF-α), which is skewed towards M1 favored polarization (high levels of CXCL-8 and IL-6, lower levels of IL-10) by 24 hours of infection, once persister cells awaken. Overall, our findings further establish the ability of persister cells to evade the innate host response and to contribute chronic infections.
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Affiliation(s)
- Cody James Hastings
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
| | - Grace Elizabeth Himmler
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
| | - Arpeet Patel
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
| | - Cláudia Nogueira Hora Marques
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, NY, 13902
- Corresponding author:
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6
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O-Acetylation of Capsular Polysialic Acid Enables Escherichia coli K1 Escaping from Siglec-Mediated Innate Immunity and Lysosomal Degradation of E. coli-Containing Vacuoles in Macrophage-Like Cells. Microbiol Spectr 2021; 9:e0039921. [PMID: 34878295 PMCID: PMC8653822 DOI: 10.1128/spectrum.00399-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli K1 causes bacteremia and meningitis in human neonates. The K1 capsule, an α2,8-linked polysialic acid (PSA) homopolymer, is its essential virulence factor. PSA is usually partially modified by O-acetyl groups. It is known that O-acetylation alters the antigenicity of PSA, but its impact on the interactions between E. coli K1 and host cells is unclear. In this study, a phase variant was obtained by passage of E. coli K1 parent strain, which expressed a capsule with 44% O-acetylation whereas the capsule of the parent strain has only 3%. The variant strain showed significantly reduced adherence and invasion to macrophage-like cells in comparison to the parent strain. Furthermore, we found that O-acetylation of PSA enhanced the modulation of trafficking of E. coli-containing vacuoles (ECV), enabling them to avoid fusing with lysosomes in these cells. Intriguingly, by using quartz crystal microbalance, we demonstrated that the PSA purified from the parent strain interacted with human sialic acid-binding immunoglobulin-like lectins (Siglecs), including Siglec-5, Siglec-7, Siglec-11, and Siglec-14. However, O-acetylated PSA from the variant interacted much less and also suppressed the production of Siglec-mediated proinflammatory cytokines. The adherence of the parent strain to human macrophage-like cells was significantly blocked by monoclonal antibodies against Siglec-11 and Siglec-14. Furthermore, the variant strain caused increased bacteremia and higher lethality in neonatal mice compared to the parent strain. These data elucidate that O-acetylation of K1 capsule enables E. coli to escape from Siglec-mediated innate immunity and lysosomal degradation; therefore, it is a strategy used by E. coli K1 to regulate its virulence. IMPORTANCEEscherichia coli K1 is a leading cause of neonatal meningitis. The mortality and morbidity of this disease remain significantly high despite antibiotic therapy. One major limitation on advances in prevention and therapy for meningitis is an incomplete understanding of its pathogenesis. E. coli K1 is surrounded by PSA, which is observed to have high-frequency variation of O-acetyl modification. Here, we present an in-depth study of the function of O-acetylation in PSA at each stage of host-pathogen interaction. We found that a high level of O-acetylation significantly interfered with Siglec-mediated bacterial adherence to macrophage-like cells, and blunted the proinflammatory response. Furthermore, the O-acetylation of PSA modulated the trafficking of ECVs to prevent them from fusing with lysosomes, enabling them to escape degradation by lysozymes within these cells. Elucidating how subtle modification of the capsule enhances bacterial defenses against host innate immunity will enable the future development of effective drugs or vaccines against infection by E. coli K1.
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7
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Huang WC, Hashimoto M, Shih YL, Wu CC, Lee MF, Chen YL, Wu JJ, Wang MC, Lin WH, Hong MY, Teng CH. Peptidoglycan Endopeptidase Spr of Uropathogenic Escherichia coli Contributes to Kidney Infections and Competitive Fitness During Bladder Colonization. Front Microbiol 2021; 11:586214. [PMID: 33391204 PMCID: PMC7774453 DOI: 10.3389/fmicb.2020.586214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/25/2020] [Indexed: 11/27/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the most common pathogen of urinary tract infections (UTIs). Antibiotic therapy is the conventional measure to manage such infections. However, the rapid emergence of antibiotic resistance has reduced the efficacy of antibiotic treatment. Given that the bacterial factors required for the full virulence of the pathogens are potential therapeutic targets, identifying such factors may facilitate the development of novel therapeutic strategies against UPEC UTIs. The peptidoglycan (PG) endopeptidase Spr (also named MepS) is required for PG biogenesis in E. coli. In the present study, we found that Spr deficiency attenuated the ability of UPEC to infect kidneys and induced a fitness defect during bladder colonization in a mouse model of UTI. Based on the liquid chromatography (LC)/mass spectrometry (MS)/MS analysis of the bacterial envelope, spr deletion changed the levels of some envelope-associated proteins, suggesting that Spr deficiency interfere with the components of the bacterial structure. Among the proteins, FliC was significantly downregulated in the spr mutant, which is resulted in reduced motility. Lack of Spr might hinder the function of the flagellar transcriptional factor FlhDC to decrease FliC expression. The motility downregulation contributed to the reduced fitness in urinary tract colonization. Additionally, spr deletion compromised the ability of UPEC to evade complement-mediated attack and to resist intracellular killing of phagocytes, consequently decreasing UPEC bloodstream survival. Spr deficiency also interfered with the UPEC morphological switch from bacillary to filamentous shapes during UTI. It is known that bacterial filamentation protects UPEC from phagocytosis by phagocytes. In conclusion, Spr deficiency was shown to compromise multiple virulence properties of UPEC, leading to attenuation of the pathogen in urinary tract colonization and bloodstream survival. These findings indicate that Spr is a potential antimicrobial target for further studies attempting to develop novel strategies in managing UPEC UTIs.
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Affiliation(s)
- Wen-Chun Huang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Masayuki Hashimoto
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ling Shih
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chia-Ching Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Mei-Feng Lee
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Ya-Lei Chen
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Jiunn-Jong Wu
- Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang Ming University, Taipei, Taiwan
| | - Ming-Cheng Wang
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Hung Lin
- Division of Nephrology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ming-Yuan Hong
- Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Hao Teng
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
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8
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Bacterial killing by complement requires direct anchoring of membrane attack complex precursor C5b-7. PLoS Pathog 2020; 16:e1008606. [PMID: 32569291 PMCID: PMC7351214 DOI: 10.1371/journal.ppat.1008606] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/10/2020] [Accepted: 05/06/2020] [Indexed: 12/22/2022] Open
Abstract
An important effector function of the human complement system is to directly kill Gram-negative bacteria via Membrane Attack Complex (MAC) pores. MAC pores are assembled when surface-bound convertase enzymes convert C5 into C5b, which together with C6, C7, C8 and multiple copies of C9 forms a transmembrane pore that damages the bacterial cell envelope. Recently, we found that bacterial killing by MAC pores requires local conversion of C5 by surface-bound convertases. In this study we aimed to understand why local assembly of MAC pores is essential for bacterial killing. Here, we show that rapid interaction of C7 with C5b6 is required to form bactericidal MAC pores on Escherichia coli. Binding experiments with fluorescently labelled C6 show that C7 prevents release of C5b6 from the bacterial surface. Moreover, trypsin shaving experiments and atomic force microscopy revealed that this rapid interaction between C7 and C5b6 is crucial to efficiently anchor C5b-7 to the bacterial cell envelope and form complete MAC pores. Using complement-resistant clinical E. coli strains, we show that bacterial pathogens can prevent complement-dependent killing by interfering with the anchoring of C5b-7. While C5 convertase assembly was unaffected, these resistant strains blocked efficient anchoring of C5b-7 and thus prevented stable insertion of MAC pores into the bacterial cell envelope. Altogether, these findings provide basic molecular insights into how bactericidal MAC pores are assembled and how bacteria evade MAC-dependent killing. In this paper we focus on how the complement system, an essential part of the immune system, kills bacteria via so-called membrane attack complex (MAC) pores. The MAC is a large, ring-shaped pore that consists of five different proteins, which is assembled when the complement system is activated on the bacterial surface. Here, we aimed to better understand how MAC pores are assembled on Escherichia coli and how clinical E. coli strains resist killing by MAC pores. We uncover that rapid recruitment of one of the MAC proteins, namely C7, is crucial to efficiently anchor the MAC precursor to the bacterial surface and ensure killing of a variety of E. coli strains via MAC pores. Furthermore, we reveal that some clinical E. coli strains prevent this efficient anchoring of MAC precursors and thereby resist bacterial killing. These insights help us to better understand how the immune system kills bacteria and how pathogenic bacteria evade this.
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9
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Cloning and identification of antimicrobial peptide, hepcidin from freshwater carp, Catla catla on pathogen challenge and PAMPs stimulation. 3 Biotech 2019; 9:341. [PMID: 31497459 DOI: 10.1007/s13205-019-1874-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Hepcidin, a cationic cysteine-rich antimicrobial peptide (AMP) acts in hormone regulation and iron homeostasis in the host body. However, the biological property of hepcidin in immune reaction remains unexplored. In aquatic milieu, environmental and pathogenic stressors cause detrimental infections, which are defended by various immunological cells and antimicrobial peptides. In this study, hepcidin gene has been cloned from freshwater carp, Catla catla. The partially cloned hepcidin consists of 200 bp nucleotide sequence encoding 66 amino acids. Nucleotide sequence showed 97% and 91% similarity with Labeo rohita and Cyprinus carpio, respectively. Expression profile revealed significant up-regulation (P ≤ 0.0001) in liver as compared to other tissues in different conditions. In Aeromonas hydrophila challenged C. catla, liver showed higher expression level of hepcidin at 72 h as compared to other tissues. In skin, hepcidin expression showed significant upraise during 24 h in Streptococcus uberis infection. In Argulus sp. infected fishes, up-regulation of hepcidin expression was noted in liver, intestine and skin. The inactivated viral antigen-stimulated fishes, a substantial rise in liver was observed implying hepcidin as an important molecule in combating the pathogenic infections in freshwater carp, C. catla. Fishes stimulated with pathogen-associated molecular patterns (PAMPs) triggered the increased expression of hepcidin mRNA in liver, kidney and skin. This study indicates the presence of hepcidin as antimicrobial peptide in neutralizing the pathogenic infection in fishes.
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10
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Cheng ZX, Guo C, Chen ZG, Yang TC, Zhang JY, Wang J, Zhu JX, Li D, Zhang TT, Li H, Peng B, Peng XX. Glycine, serine and threonine metabolism confounds efficacy of complement-mediated killing. Nat Commun 2019; 10:3325. [PMID: 31346171 PMCID: PMC6658569 DOI: 10.1038/s41467-019-11129-5] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 06/24/2019] [Indexed: 11/28/2022] Open
Abstract
Serum resistance is a poorly understood but common trait of some difficult-to-treat pathogenic strains of bacteria. Here, we report that glycine, serine and threonine catabolic pathway is down-regulated in serum-resistant Escherichia coli, whereas exogenous glycine reverts the serum resistance and effectively potentiates serum to eliminate clinically-relevant bacterial pathogens in vitro and in vivo. We find that exogenous glycine increases the formation of membrane attack complex on bacterial membrane through two previously unrecognized regulations: 1) glycine negatively and positively regulates metabolic flux to purine biosynthesis and Krebs cycle, respectively. 2) α-Ketoglutarate inhibits adenosine triphosphate synthase, which in together promote the formation of cAMP/CRP regulon to increase the expression of complement-binding proteins HtrE, NfrA, and YhcD. The results could lead to effective strategies for managing the infection with serum-resistant bacteria, an especially valuable approach for treating individuals with weak acquired immunity but a normal complement system. Serum-resistant bacteria can escape complement killing in the bloodstream. Here, using metabolomics and metabolite perturbations, the authors describe an altered metabolic state in serum-resistant Escherichia coli and show that exogenous glycine potentiates elimination of pathogenic bacteria in vivo.
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Affiliation(s)
- Zhi-Xue Cheng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China.,Laboratory for Marine Biology and Biotechnology, Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Chang Guo
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China
| | - Zhuang-Gui Chen
- Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, People's Republic of China
| | - Tian-Ci Yang
- Zhongshan Hospital of Xiamen University, Xiamen, 361004, People's Republic of China
| | - Jian-Ying Zhang
- Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan, 450052, People's Republic of China
| | - Jie Wang
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China
| | - Jia-Xin Zhu
- Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, People's Republic of China
| | - Dan Li
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China
| | - Tian-Tuo Zhang
- Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, People's Republic of China.
| | - Hui Li
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China. .,Laboratory for Marine Biology and Biotechnology, Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China. .,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
| | - Bo Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China. .,Laboratory for Marine Biology and Biotechnology, Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China. .,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
| | - Xuan-Xian Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou, 510006, People's Republic of China. .,Laboratory for Marine Biology and Biotechnology, Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China. .,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
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11
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Ermert D, Laabei M, Weckel A, Mörgelin M, Lundqvist M, Björck L, Ram S, Linse S, Blom AM. The Molecular Basis of Human IgG-Mediated Enhancement of C4b-Binding Protein Recruitment to Group A Streptococcus. Front Immunol 2019; 10:1230. [PMID: 31214187 PMCID: PMC6557989 DOI: 10.3389/fimmu.2019.01230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/14/2019] [Indexed: 11/25/2022] Open
Abstract
Streptococcus pyogenes infects over 700 million people worldwide annually. Immune evasion strategies employed by the bacteria include binding of the complement inhibitors, C4b-binding protein (C4BP) and Factor H in a human-specific manner. We recently showed that human IgG increased C4BP binding to the bacterial surface, which promoted streptococcal immune evasion and increased mortality in mice. We sought to identify how IgG promotes C4BP binding to Protein H, a member of the M protein family. Dimerization of Protein H is pivotal for enhanced binding to human C4BP. First, we illustrated that Protein H, IgG, and C4BP formed a tripartite complex. Second, surface plasmon resonance revealed that Protein H binds IgG solely through Fc, but not Fab domains, and with high affinity (IgG-Protein H: KD = 0.4 nM; IgG-Fc-Protein H: KD ≤ 1.6 nM). Each IgG binds two Protein H molecules, while up to six molecules of Protein H bind one C4BP molecule. Third, interrupting Protein H dimerization either by raising temperature to 41°C or with a synthetic peptide prevented IgG-Protein H interactions. IgG-Fc fragments or monoclonal human IgG permitted maximal C4BP binding when used at concentrations from 0.1 to 10 mg/ml. In contrast, pooled human IgG enhanced C4BP binding at concentrations up to 1 mg/ml; decreased C4BP binding at 10 mg/ml occurred probably because of Fab-streptococcal interactions at these high IgG concentrations. Taken together, our data show how S. pyogenes exploits human IgG to evade complement and enhance its virulence. Elucidation of this mechanism could aid design of new therapeutics against S. pyogenes.
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Affiliation(s)
- David Ermert
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden.,Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Maisem Laabei
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Antonin Weckel
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | | | - Martin Lundqvist
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Lund, Sweden
| | - Lars Björck
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Lund, Sweden
| | - Anna M Blom
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
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12
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Lang SN, Germerodt S, Glock C, Skerka C, Zipfel PF, Schuster S. Molecular crypsis by pathogenic fungi using human factor H. A numerical model. PLoS One 2019; 14:e0212187. [PMID: 30779817 PMCID: PMC6380567 DOI: 10.1371/journal.pone.0212187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 01/29/2019] [Indexed: 02/02/2023] Open
Abstract
Molecular mimicry is the formation of specific molecules by microbial pathogens to avoid recognition and attack by the immune system of the host. Several pathogenic Ascomycota and Zygomycota show such a behaviour by utilizing human complement factor H to hide in the blood stream. We call this type of mimicry molecular crypsis. Such a crypsis can reach a point where the immune system can no longer clearly distinguish between self and non-self cells. Thus, a trade-off between attacking disguised pathogens and erroneously attacking host cells has to be made. Based on signalling theory and protein-interaction modelling, we here present a mathematical model of molecular crypsis of pathogenic fungi using the example of Candida albicans. We tackle the question whether perfect crypsis is feasible, which would imply that protection of human cells by complement factors would be useless. The model identifies pathogen abundance relative to host cell abundance as the predominant factor influencing successful or unsuccessful molecular crypsis. If pathogen cells gain a (locally) quantitative advantage over host cells, even autoreactivity may occur. Our new model enables insights into the mechanisms of candidiasis-induced sepsis and complement-associated autoimmune diseases.
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Affiliation(s)
- Stefan N. Lang
- Dept. of Bioinformatics, Friedrich Schiller University Jena, Jena, Germany
| | | | - Christina Glock
- Dept. of Bioinformatics, Friedrich Schiller University Jena, Jena, Germany
| | - Christine Skerka
- Dept. of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany
| | - Peter F. Zipfel
- Dept. of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Stefan Schuster
- Dept. of Bioinformatics, Friedrich Schiller University Jena, Jena, Germany
- * E-mail:
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13
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Lindholm M, Min Aung K, Nyunt Wai S, Oscarsson J. Role of OmpA1 and OmpA2 in Aggregatibacter actinomycetemcomitans and Aggregatibacter aphrophilus serum resistance. J Oral Microbiol 2018; 11:1536192. [PMID: 30598730 PMCID: PMC6225413 DOI: 10.1080/20002297.2018.1536192] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/03/2018] [Accepted: 10/10/2018] [Indexed: 12/27/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans and Aggregatibacter aphrophilus belong to the HACEK group of fastidious Gram-negative organisms, a recognized cause of infective endocarditis. A. actinomycetemcomitans is also implicated in aggressive forms of periodontitis. We demonstrated that A. aphrophilus strains, as A. actinomycetemcomitans are ubiquitously serum resistant. Both species encode two Outer membrane protein A paralogues, here denoted OmpA1 and OmpA2. As their respective pangenomes contain several OmpA1 and OmpA2 alleles, they represent potential genotypic markers. A naturally competent strain of A. actinomycetemcomitans and A. aphrophilus, respectively were used to elucidate if OmpA1 and OmpA2 contribute to serum resistance. Whereas OmpA1 was critical for survival of A. actinomycetemcomitans D7SS in 50% normal human serum (NHS), serum resistant ompA1 mutants were fortuitously obtained, expressing enhanced levels of OmpA2. Similarly, OmpA1 rather than OmpA2 was a major contributor to serum resistance of A. aphrophilus HK83. Far-Western blot revealed that OmpA1AA, OmpA2AA, and OmpA1AP can bind to C4-binding protein, an inhibitor of classical and mannose-binding lectin (MBL) complement activation. Indeed, ompA1 mutants were susceptible to these pathways, but also to alternative complement activation. This may at least partly reflect a compromised outer membrane integrity but is also consistent with alternative mechanisms involved in OmpA-mediated serum resistance.
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Affiliation(s)
- Mark Lindholm
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Kyaw Min Aung
- Department of Molecular Biology and the Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Sun Nyunt Wai
- Department of Molecular Biology and the Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
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14
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Three tandem promoters, together with IHF, regulate growth phase dependent expression of the Escherichia coli kps capsule gene cluster. Sci Rep 2017; 7:17924. [PMID: 29263430 PMCID: PMC5738388 DOI: 10.1038/s41598-017-17891-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 12/01/2017] [Indexed: 02/02/2023] Open
Abstract
In this study we characterise three tandem promoters (PR1-1, PR1-2 and PR1-3) within the PR1 regulatory region of the Escherichia coli kps capsule gene cluster. Transcription from promoter PR1-2 was dependent on the activity of the upstream promoter PR1-1, which activated PR1-2 via transcription coupled DNA supercoiling. During growth at 37 °C a temporal pattern of transcription from all three promoters was observed with maximum transcriptional activity evident during mid-exponential phase followed by a sharp decrease in activity as the cells enter stationary phase. The growth phase dependent transcription was regulated by Integration Host Factor (IHF), which bound within the PR1 region to repress transcription from PR1-2 and PR1-3. This pattern of transcription was mirrored by growth phase dependent expression of the K1 capsule. Overall these data reveal a complex pattern of transcriptional regulation for an important virulence factor with IHF playing a role in regulating growth phase expression.
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15
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Fernández FJ, Gómez S, Vega MC. Pathogens' toolbox to manipulate human complement. Semin Cell Dev Biol 2017; 85:98-109. [PMID: 29221973 DOI: 10.1016/j.semcdb.2017.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/30/2017] [Accepted: 12/03/2017] [Indexed: 12/15/2022]
Abstract
The surveillance and pathogen fighting functions of the complement system have evolved to protect mammals from life-threatening infections. In turn, pathogens have developed complex molecular mechanisms to subvert, divert and evade the effector functions of the complement. The study of complement immunoevasion by pathogens sheds light on their infection drivers, knowledge that is essential to implement therapies. At the same time, complement evasion also acts as a discovery ground that reveals important aspects of how complement works under physiological conditions. In recent years, complex interrelationships between infection insults and the onset of autoimmune and complement dysregulation diseases have led to propose that encounters with pathogens can act as triggering factors for disease. The correct management of these diseases involves the recognition of their triggering factors and the development and administration of complement-associated molecular therapies. Even more recently, unsuspected proteins from pathogens have been shown to possess moonlighting functions as virulence factors, raising the possibility that behind the first line of virulence factors there be many more pathogen proteins playing secondary, helping and supporting roles for the pathogen to successfully establish infections. In an era where antibiotics have a progressively reduced effect on the management and control of infectious diseases worldwide, knowledge on the mechanisms of pathogenic invasion and evasion look more necessary and pressing than ever.
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Affiliation(s)
| | - Sara Gómez
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
| | - M Cristina Vega
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
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16
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Jiang XF, Liu ZF, Lin AF, Xiang LX, Shao JZ. Coordination of Bactericidal and Iron Regulatory Functions of Hepcidin in Innate Antimicrobial Immunity in a Zebrafish Model. Sci Rep 2017; 7:4265. [PMID: 28655927 PMCID: PMC5487360 DOI: 10.1038/s41598-017-04069-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/09/2017] [Indexed: 01/31/2023] Open
Abstract
Hepcidin acts as both an antimicrobial peptide and a hormonal regulator of iron homeostasis; however, the biological significance of this dual-function in immune reactions remains elusive. In this study, we provide experimental evidence regarding the coordination of this dual-function in the innate antimicrobial immunity using a zebrafish model. The transcription of hepcidin gene was significantly upregulated in liver by Aeromonas hydrophila (A.h) DNA stimulation, which was accompanied by an increase of hepcidin protein and a decrease of iron concentration in serum. Thus, an enhanced bactericidal activity against A.h and Escherichia coli and inhibitory effects on A.h growth and OmpA expression were observed in A.h cells, the latter of which made the bacterium more susceptible to complement attack. The enhanced bacteriostatic activities in serum following the stimulation were dramatically impaired by neutralizing hepcidin or restoring iron to the samples. Immuno-protection assay showed that zebrafish administrated with A.h DNA or designed CpG-ODNs had a significantly enhanced defence against A.h and Vibrio alginolyticus infections, which was also eliminated by the neutralization of hepcidin. Results indicate that the induction of hepcidin leads to the decrease of iron in circulation, which eventually limits iron availability to invading microorganisms, thus contributing to host defence.
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Affiliation(s)
- Xiao-Feng Jiang
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China.,Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, 310058, People's Republic of China
| | - Zhi-Fei Liu
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China.,Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, 310058, People's Republic of China
| | - Ai-Fu Lin
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China.,Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, 310058, People's Republic of China
| | - Li-Xin Xiang
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China. .,Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, 310058, People's Republic of China.
| | - Jian-Zhong Shao
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, People's Republic of China. .,Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou, 310058, People's Republic of China. .,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, People's Republic of China.
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17
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Abreu AG, Barbosa AS. How Escherichia coli Circumvent Complement-Mediated Killing. Front Immunol 2017; 8:452. [PMID: 28473832 PMCID: PMC5397495 DOI: 10.3389/fimmu.2017.00452] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/03/2017] [Indexed: 12/19/2022] Open
Abstract
Complement is a crucial arm of the innate immune response against invading bacterial pathogens, and one of its main functions is to recognize and destroy target cells. Similar to other pathogens, Escherichia coli has evolved mechanisms to overcome complement activation. It is well known that capsular polysaccharide may confer resistance to complement-mediated killing and phagocytosis, being one of the strategies adopted by this bacterium to survive in serum. In addition, proteases produced by E. coli have been shown to downregulate the complement system. Pic, an autotransporter secreted by different pathogens in the Enterobacteriaceae family, is able to cleave C2, C3/C3b, and C4/C4b and works synergistically with human Factor I and Factor H (FH), thereby promoting inactivation of C3b. Extracellular serine protease P, a serine protease of enterohemorrhagic E. coli (EHEC), downregulates complement activation by cleaving C3/C3b and C5. StcE, a metalloprotease secreted by EHEC, inhibits the classical complement-mediated cell lysis by potentiating the action of C1 inhibitor, and the periplasmic protease Prc contributes to E. coli complement evasion by interfering with the classical pathway activation and by preventing membrane attack complex deposition. Finally, it has been described that E. coli proteins interact with negative complement regulators to modulate complement activation. The functional consequences resulting from the interaction of outer membrane protein A, new lipoprotein I, outer membrane protein W, and Stx2 with proteins of the FH family and C4b-binding protein (C4BP) are discussed in detail. In brief, in this review, we focused on the different mechanisms used by pathogenic E. coli to circumvent complement attack, allowing these bacteria to promote a successful infection.
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Affiliation(s)
- Afonso G Abreu
- Programa de Pós-Graduação em Biologia Parasitária, CEUMA University, São Luís, Brazil.,Programa de Pós-Graduação em Ciências da Saúde, Federal University of Maranhão, São Luís, Brazil
| | - Angela S Barbosa
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
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18
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Caine JA, Coburn J. Multifunctional and Redundant Roles of Borrelia burgdorferi Outer Surface Proteins in Tissue Adhesion, Colonization, and Complement Evasion. Front Immunol 2016; 7:442. [PMID: 27818662 PMCID: PMC5073149 DOI: 10.3389/fimmu.2016.00442] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/07/2016] [Indexed: 12/24/2022] Open
Abstract
Borrelia burgdorferi is the causative agent of Lyme disease in the U.S., with at least 25,000 cases reported to the CDC each year. B. burgdorferi is thought to enter and exit the bloodstream to achieve rapid dissemination to distal tissue sites during infection. Travel through the bloodstream requires evasion of immune surveillance and pathogen clearance in the host, a process at which B. burgdorferi is adept. B. burgdorferi encodes greater than 19 adhesive outer surface proteins many of which have been found to bind to host cells or components of the extracellular matrix. Several others bind to host complement regulatory factors, in vitro. Production of many of these adhesive proteins is tightly regulated by environmental cues, and some have been shown to aid in vascular interactions and tissue colonization, as well as survival in the blood, in vivo. Recent work has described multifaceted and redundant roles of B. burgdorferi outer surface proteins in complement component interactions and tissue targeted adhesion and colonization, distinct from their previously identified in vitro binding capabilities. Recent insights into the multifunctional roles of previously well-characterized outer surface proteins such as BBK32, DbpA, CspA, and OspC have changed the way we think about the surface proteome of these organisms during the tick-mammal life cycle. With the combination of new and old in vivo models and in vitro techniques, the field has identified distinct ligand binding domains on BBK32 and DbpA that afford tissue colonization or blood survival to B. burgdorferi. In this review, we describe the multifunctional and redundant roles of many adhesive outer surface proteins of B. burgdorferi in tissue adhesion, colonization, and bloodstream survival that, together, promote the survival of Borrelia spp. throughout maintenance in their multi-host lifestyle.
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Affiliation(s)
- Jennifer A. Caine
- Division of Infectious Disease, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jenifer Coburn
- Division of Infectious Disease, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
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19
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Soto E, Marchi S, Beierschmitt A, Kearney M, Francis S, VanNess K, Vandenplas M, Thrall M, Palmour R. Interaction of non-human primate complement and antibodies with hypermucoviscous Klebsiella pneumoniae. Vet Res 2016; 47:40. [PMID: 26951091 PMCID: PMC4782414 DOI: 10.1186/s13567-016-0325-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 02/17/2016] [Indexed: 01/31/2023] Open
Abstract
Emergent hypermucoviscosity (HMV) phenotypes of Klebsiella pneumoniae have been associated with increased invasiveness and pathogenicity in primates. In this study, we investigated the interaction of African green monkeys (AGM) (Chlorocebus aethiops sabaeus) complement and antibody with HMV and non-HMV isolates as in vitro models of primate infection. Significantly greater survival of HMV isolates was evident after incubation in normal serum or whole blood (p < 0.05) of AGM donors when compared to non-HMV strains. Greater survival of HMV strains (p < 0.05) was found after incubation in whole blood and serum from seropositive donors when compared to seronegative donor samples. Additionally, significantly greater amounts of K. pneumoniae were phagocytozed by AGM leukocytes when complement was active (p < 0.05), but no difference in uptake was observed when serum from seropositive or seronegative animals was used in challenged cells utilizing flow cytometry. Results demonstrate that interaction of cellular and humoral immune elements play a role in the in vitro killing of K. pneumoniae, particularly HMV isolates. Neither AGM serum, nor washed whole blood effectively killed HMV isolates; however, assays using heparinized whole blood of seronegative donors significantly reduced viability of HMV and non-HMV strains. The lack of bacterial killing observed in seropositive donors treatments could be at least partially associated with low IgG2 present in these animals. A better understanding of the pathogenesis of klebsiellosis in primates and host immune response is necessary to identify surface molecules that can induce both opsonizing and bactericidal antibody facilitating killing of Klebsiella, and the development of vaccines in human and animals.
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Affiliation(s)
- Esteban Soto
- Department of Epidemiology and Medicine, University of California, Davis-School of Veterinary Medicine, Davis, CA, USA. .,Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.
| | - Sylvia Marchi
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.
| | - Amy Beierschmitt
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies. .,Behavioural Science Foundation, Estridge Estate, Basseterre, St. Kitts, West Indies.
| | - Michael Kearney
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, USA.
| | - Stewart Francis
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.
| | - Kimberly VanNess
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.
| | - Michel Vandenplas
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.
| | - MaryAnna Thrall
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, St. Kitts, West Indies.
| | - Roberta Palmour
- Behavioural Science Foundation, Estridge Estate, Basseterre, St. Kitts, West Indies.
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20
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Doran KS, Fulde M, Gratz N, Kim BJ, Nau R, Prasadarao N, Schubert-Unkmeir A, Tuomanen EI, Valentin-Weigand P. Host-pathogen interactions in bacterial meningitis. Acta Neuropathol 2016; 131:185-209. [PMID: 26744349 PMCID: PMC4713723 DOI: 10.1007/s00401-015-1531-z] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 12/26/2022]
Abstract
Bacterial meningitis is a devastating disease occurring worldwide with up to half of the survivors left with permanent neurological sequelae. Due to intrinsic properties of the meningeal pathogens and the host responses they induce, infection can cause relatively specific lesions and clinical syndromes that result from interference with the function of the affected nervous system tissue. Pathogenesis is based on complex host–pathogen interactions, some of which are specific for certain bacteria, whereas others are shared among different pathogens. In this review, we summarize the recent progress made in understanding the molecular and cellular events involved in these interactions. We focus on selected major pathogens, Streptococcus pneumonia, S. agalactiae (Group B Streptococcus), Neisseria meningitidis, and Escherichia coli K1, and also include a neglected zoonotic pathogen, Streptococcus suis. These neuroinvasive pathogens represent common themes of host–pathogen interactions, such as colonization and invasion of mucosal barriers, survival in the blood stream, entry into the central nervous system by translocation of the blood–brain and blood–cerebrospinal fluid barrier, and induction of meningeal inflammation, affecting pia mater, the arachnoid and subarachnoid spaces.
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21
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Yang WE, Suchindran S, Nicholson BP, McClain MT, Burke T, Ginsburg GS, Harro CD, Chakraborty S, Sack DA, Woods CW, Tsalik EL. Transcriptomic Analysis of the Host Response and Innate Resilience to Enterotoxigenic Escherichia coli Infection in Humans. J Infect Dis 2016; 213:1495-504. [PMID: 26787651 DOI: 10.1093/infdis/jiv593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/27/2015] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Enterotoxigenic Escherichia coli (ETEC) is a globally prevalent cause of diarrhea. Though usually self-limited, it can be severe and debilitating. Little is known about the host transcriptional response to infection. We report the first gene expression analysis of the human host response to experimental challenge with ETEC. METHODS We challenged 30 healthy adults with an unattenuated ETEC strain, and collected serial blood samples shortly after inoculation and daily for 8 days. We performed gene expression analysis on whole peripheral blood RNA samples from subjects in whom severe symptoms developed (n = 6) and a subset of those who remained asymptomatic (n = 6) despite shedding. RESULTS Compared with baseline, symptomatic subjects demonstrated significantly different expression of 406 genes highlighting increased immune response and decreased protein synthesis. Compared with asymptomatic subjects, symptomatic subjects differentially expressed 254 genes primarily associated with immune response. This comparison also revealed 29 genes differentially expressed between groups at baseline, suggesting innate resilience to infection. Drug repositioning analysis identified several drug classes with potential utility in augmenting immune response or mitigating symptoms. CONCLUSIONS There are statistically significant and biologically plausible differences in host gene expression induced by ETEC infection. Differential baseline expression of some genes may indicate resilience to infection.
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Affiliation(s)
- William E Yang
- Duke University School of Medicine, Department of Medicine, Duke University Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University
| | - Sunil Suchindran
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University
| | - Bradly P Nicholson
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University Internal Medicine Service, Durham VA Medical Center, Duke University Medical Center, North Carolina
| | - Micah T McClain
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University Internal Medicine Service, Durham VA Medical Center, Duke University Medical Center, North Carolina Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, North Carolina
| | - Thomas Burke
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University
| | - Geoffrey S Ginsburg
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University
| | - Clayton D Harro
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Subhra Chakraborty
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - David A Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Christopher W Woods
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University Internal Medicine Service, Durham VA Medical Center, Duke University Medical Center, North Carolina Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, North Carolina
| | - Ephraim L Tsalik
- Center for Applied Genomics & Precision Medicine, Department of Medicine, Duke University Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, North Carolina Emergency Medicine Service, Durham VA Medical Center, North Carolina
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22
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Ermert D, Blom AM. C4b-binding protein: The good, the bad and the deadly. Novel functions of an old friend. Immunol Lett 2015; 169:82-92. [PMID: 26658464 DOI: 10.1016/j.imlet.2015.11.014] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 11/26/2015] [Accepted: 11/27/2015] [Indexed: 01/29/2023]
Abstract
C4b-binding protein (C4BP) is best known as a potent soluble inhibitor of the classical and lectin pathways of the complement system. This large 500 kDa multimeric plasma glycoprotein is expressed mainly in the liver but also in lung and pancreas. It consists of several identical 75 kDa α-chains and often also one 40 kDa β-chain, both of which are mainly composed of complement control protein (CCP) domains. Structure-function studies revealed that one crucial binding site responsible for inhibition of complement is located to CCP1-3 of the α-chain. Binding of anticoagulant protein S to the CCP1 of the β-chain provides C4BP with the ability to strongly bind apoptotic and necrotic cells in order to prevent inflammation arising from activation of complement by these cells. Further, C4BP interacts strongly with various types of amyloid and enhances fibrillation of islet amyloid polypeptide secreted from pancreatic beta cells, which may attenuate pro-inflammatory and cytotoxic effects of this amyloid. Full deficiency of C4BP has not been identified but non-synonymous alterations in its sequence have been found in haemolytic uremic syndrome and recurrent pregnancy loss. Furthermore, C4BP is bound by several bacterial pathogens, notably Streptococcus pyogenes, which due to inhibition of complement and enhancement of bacterial adhesion to endothelial cells provides these bacteria with a survival advantage in the host. Thus, depending on the context, C4BP has a protective or detrimental role in the organism.
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Affiliation(s)
- David Ermert
- Lund University, Department of Translational Medicine, Division of Medical Protein Chemistry, Inga Marie Nilssons Street 53, Malmö, 20502, Sweden.
| | - Anna M Blom
- Lund University, Department of Translational Medicine, Division of Medical Protein Chemistry, Inga Marie Nilssons Street 53, Malmö, 20502, Sweden.
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23
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Vega-Manriquez X, Huerta-Ascencio L, Martínez-Gómez D, López-Vidal Y, Verdugo-Rodríguez A. Influence of heat-labile serum components in the presence of OmpA on the outer membrane of Salmonella gallinarum. Arch Microbiol 2015; 198:161-9. [PMID: 26597854 DOI: 10.1007/s00203-015-1174-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 11/06/2015] [Accepted: 11/12/2015] [Indexed: 11/24/2022]
Abstract
Salmonella gallinarum is the causative agent of fowl typhoid. Being a Gram-negative bacteria, its outer membrane proteins (OMP) can be regulated by different microenvironments. S. gallinarum was cultured under the following conditions: nutrient broth (NB), NB supplemented with serum from specific pathogen-free birds (NBS) and NB with serum incubated at 56 °C prior to incubation with the bacteria (NBSD); OMP were subsequently extracted. Several changes were observed in the apparent expression of OMP, mainly a decrease in an OMP with a size of 30 kDa, approximately, under the NBS condition. In contrast, the same event was not observed in NB and NBSD when using one- and two-dimensional polyacrylamide gels (SDS-PAGE). Using the OMP with a size of 30 kDa, approximately, as antigen in indirect ELISA, we were able to differentiate serum from healthy and vaccinated birds, as well as birds infected with S. gallinarum and S. enteritidis. The amino-terminal of this protein was sequenced, showing 100 % identity with OmpA of S. typhimurium. Subsequently, we designed primers to amplify the gene by PCR. The partial sequence of the amplified gene showed 100 % identity with OmpA of S. gallinarum. (1) Heat-labile serum components influence the presence of OmpA in the OM of S. gallinarum; (2) by the way of ELISA, OmpA allows to specifically differentiate healthy from diseased birds.
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Affiliation(s)
- X Vega-Manriquez
- Facultad de Agronomía y Veterinaria, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico
| | - L Huerta-Ascencio
- Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootencnia, Universidad Nacional Autónoma de México, Circuito exterior S/N, Ciudad Universitaria, UNAM CU, Coyoacan México, 04510, México City, Mexico
| | - D Martínez-Gómez
- Departamento de Producción Agrícola, Universidad Autónoma Metropolitana-Unidad Xochimilco, México City, Mexico
| | - Y López-Vidal
- Programa de Inmunología Molecular Microbiana, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, Mexico
| | - A Verdugo-Rodríguez
- Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootencnia, Universidad Nacional Autónoma de México, Circuito exterior S/N, Ciudad Universitaria, UNAM CU, Coyoacan México, 04510, México City, Mexico.
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24
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Dale AP, Woodford N. Extra-intestinal pathogenic Escherichia coli (ExPEC): Disease, carriage and clones. J Infect 2015; 71:615-26. [PMID: 26409905 DOI: 10.1016/j.jinf.2015.09.009] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/16/2015] [Indexed: 10/23/2022]
Abstract
Extra-intestinal pathogenic Escherichia coli (ExPEC) have a complex phylogeny, broad virulence factor (VF) armament and significant genomic plasticity, and are associated with a spectrum of host infective syndromes ranging from simple urinary tract infection to life-threatening bacteraemia. Their importance as pathogens has come to the fore in recent years, particularly in the context of the global emergence of hyper-virulent and antibiotic resistant strains. Despite this, the mechanisms underlying ExPEC transmission dynamics and clonal selection remain poorly understood. Large-scale epidemiological and clinical studies are urgently required to ascertain the mechanisms underlying these processes to enable the development of novel evidence-based preventative and therapeutic strategies. In the current review, we provide a concise summary of the methods utilised for ExPEC phylogenetic delineation before exploring in detail the associations between ExPEC VFs and site-specific disease. We then consider the role of ExPEC as an intestinal colonist and outline known associations between ExPEC clonal variation, specific disease syndromes and antibiotic resistance.
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Affiliation(s)
- Adam P Dale
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, South Academic Block, Tremona Road, Southampton SO16 6YD, UK.
| | - Neil Woodford
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, Reference Microbiology Services, Public Health England, London NW9 5EQ, UK; The NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance at Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0HS, UK
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25
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Krishnan S, Chang AC, Hodges J, Couraud PO, Romero IA, Weksler B, Nicholson BA, Nolan LK, Prasadarao NV. Serotype O18 avian pathogenic and neonatal meningitis Escherichia coli strains employ similar pathogenic strategies for the onset of meningitis. Virulence 2015; 6:777-86. [PMID: 26407066 DOI: 10.1080/21505594.2015.1091914] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Neonatal meningitis Escherichia coli K1 (NMEC) are thought to be transmitted from mothers to newborns during delivery or by nosocomial infections. However, the source of E. coli K1 causing these infections is not clear. Avian pathogenic E. coli (APEC) have the potential to cause infection in humans while human E. coli have potential to cause colibacillosis in poultry, suggesting that these strains may lack host specificity. APEC strains are capable of causing meningitis in newborn rats; however, it is unclear whether these bacteria use similar mechanisms to that of NMEC to establish disease. Using four representative APEC and NMEC strains that belong to serotype O18, we demonstrate that these strains survive in human serum similar to that of the prototypic NMEC strain E44, a derivative of RS218. These bacteria also bind and enter both macrophages and human cerebral microvascular endothelial cells (HCMEC/D3) with similar frequency as that of E44. The amino acid sequences of the outer membrane protein A (OmpA), an important virulence factor in the pathogenesis of meningitis, are identical within these representative APEC and NMEC strains. Further, these strains also require FcγRI-α chain (CD64) and Ecgp96 as receptors for OmpA in macrophages and HCMEC/D3, respectively, to bind and enter these cells. APEC and NMEC strains induce meningitis in newborn mice with varying degree of pathology in the brains as assessed by neutrophil recruitment and neuronal apoptosis. Together, these results suggest that serotype O18 APEC strains utilize similar pathogenic mechanisms as those of NMEC strains in causing meningitis.
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Affiliation(s)
- Subramanian Krishnan
- a Division of Infectious Diseases and Department of Pediatrics; Children's Hospital Los Angeles , CA USA
| | - Alexander C Chang
- a Division of Infectious Diseases and Department of Pediatrics; Children's Hospital Los Angeles , CA USA
| | - Jacqueline Hodges
- a Division of Infectious Diseases and Department of Pediatrics; Children's Hospital Los Angeles , CA USA
| | - Pierre-Olivier Couraud
- b Inserm; Institut Cochin, Paris, France; Université Paris Descartes; Sorbonne Paris Cité , Paris , France
| | - Ignacio A Romero
- c Department of Life ; Health and Chemical Sciences; Open University ; Milton Keynes , UK
| | - Babette Weksler
- d Division of Hematology and Medical Oncology; Weill Cornell Medical College ; New York , NY USA
| | - Bryon A Nicholson
- e Department of Veterinary Microbiology and Preventive Medicine ; College of Veterinary Medicine; Iowa State University ; Ames , IA USA
| | - Lisa K Nolan
- e Department of Veterinary Microbiology and Preventive Medicine ; College of Veterinary Medicine; Iowa State University ; Ames , IA USA
| | - Nemani V Prasadarao
- a Division of Infectious Diseases and Department of Pediatrics; Children's Hospital Los Angeles , CA USA.,f Department of Surgery ; Children's Hospital Los Angeles; University of Southern California ; Los Angeles , CA USA
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26
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Kieselbach T, Zijnge V, Granström E, Oscarsson J. Proteomics of Aggregatibacter actinomycetemcomitans Outer Membrane Vesicles. PLoS One 2015; 10:e0138591. [PMID: 26381655 PMCID: PMC4575117 DOI: 10.1371/journal.pone.0138591] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 09/01/2015] [Indexed: 11/18/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is an oral and systemic pathogen associated with aggressive forms of periodontitis and with endocarditis. Outer membrane vesicles (OMVs) released by this species have been demonstrated to deliver effector proteins such as cytolethal distending toxin (CDT) and leukotoxin (LtxA) into human host cells and to act as triggers of innate immunity upon carriage of NOD1- and NOD2-active pathogen-associated molecular patterns (PAMPs). To improve our understanding of the pathogenicity-associated functions that A. actinomycetemcomitans exports via OMVs, we studied the proteome of density gradient-purified OMVs from a rough-colony type clinical isolate, strain 173 (serotype e) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This analysis yielded the identification of 151 proteins, which were found in at least three out of four independent experiments. Data are available via ProteomeXchange with identifier PXD002509. Through this study, we not only confirmed the vesicle-associated release of LtxA, and the presence of proteins, which are known to act as immunoreactive antigens in the human host, but we also identified numerous additional putative virulence-related proteins in the A. actinomycetemcomitans OMV proteome. The known and putative functions of these proteins include immune evasion, drug targeting, and iron/nutrient acquisition. In summary, our findings are consistent with an OMV-associated proteome that exhibits several offensive and defensive functions, and they provide a comprehensive basis to further disclose roles of A. actinomycetemcomitans OMVs in periodontal and systemic disease.
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Affiliation(s)
| | - Vincent Zijnge
- Center for Dentistry and Oral Hygiene, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
- * E-mail:
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27
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Li MF, Sun L, Li J. Edwardsiella tarda evades serum killing by preventing complement activation via the alternative pathway. FISH & SHELLFISH IMMUNOLOGY 2015; 43:325-329. [PMID: 25575477 DOI: 10.1016/j.fsi.2014.12.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/01/2014] [Accepted: 12/26/2014] [Indexed: 06/04/2023]
Abstract
Edwardsiella tarda is a Gram-negative bacterium with a broad host range that includes a wide variety of farmed fish as well as humans. E. tarda has long been known to be able to survive in host serum, but the relevant mechanism is unclear. In this study, we investigated the fundamental question, i.e. whether E. tarda activated serum complement or not. We found that (i) when incubated with flounder serum, E. tarda exhibited a high survival rate (87.6%), which was slightly but significantly reduced in the presence of Mg(2+); (ii) E. tarda-incubated serum possessed strong hemolytic activity and bactericidal activity, (iii) compared to the serum incubated with a complement-sensitive laboratory Escherichia coli strain, E. tarda-incubated serum exhibited much less chemotactic activity, (iv) in contrast to the serum incubated with live E. tarda, the serum incubated with heat-inactivated E. tarda exhibited no apparent hemolytic capacity. Taken together, these results indicate for the first time that E. tarda circumvents serum attack by preventing, to a large extent, complement activation via the alternative pathway, and that heat-labile surface structures likely play an essential role in the complement evasion of E. tarda.
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Affiliation(s)
- Mo-fei Li
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Li Sun
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
| | - Jun Li
- School of Biological Sciences, Lake Superior State University, 650 W. Easterday Ave., Sault Ste Marie, MI 49783, USA.
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28
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Jongerius I, Schuijt TJ, Mooi FR, Pinelli E. Complement evasion by Bordetella pertussis: implications for improving current vaccines. J Mol Med (Berl) 2015; 93:395-402. [PMID: 25686752 PMCID: PMC4366546 DOI: 10.1007/s00109-015-1259-1] [Citation(s) in RCA: 26] [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: 12/11/2014] [Revised: 01/19/2015] [Accepted: 01/27/2015] [Indexed: 12/17/2022]
Abstract
Bordetella pertussis causes whooping cough or pertussis, a highly contagious disease of the respiratory tract. Despite high vaccination coverage, reported cases of pertussis are rising worldwide and it has become clear that the current vaccines must be improved. In addition to the well-known protective role of antibodies and T cells during B. pertussis infection, innate immune responses such as the complement system play an essential role in B. pertussis killing. In order to evade this complement activation and colonize the human host, B. pertussis expresses several molecules that inhibit complement activation. Interestingly, one of the known complement evasion proteins, autotransporter Vag8, is highly expressed in the recently emerged B. pertussis isolates. Here, we describe the current knowledge on how B. pertussis evades complement-mediated killing. In addition, we compare this to complement evasion strategies used by other bacterial species. Finally, we discuss the consequences of complement evasion by B. pertussis on adaptive immunity and how identification of the bacterial molecules and the mechanisms involved in complement evasion might help improve pertussis vaccines.
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Affiliation(s)
- Ilse Jongerius
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, The Netherlands
- Present Address: Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Tim J. Schuijt
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, The Netherlands
- Present Address: Department of Clinical Chemistry, Hematology and Immunology, Diakonessenhuis, Bosboomstraat 1, 3582 KE Utrecht, The Netherlands
| | - Frits R. Mooi
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, The Netherlands
| | - Elena Pinelli
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, The Netherlands
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29
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Phenotypic heterogeneity enables uropathogenic Escherichia coli to evade killing by antibiotics and serum complement. Infect Immun 2015; 83:1056-67. [PMID: 25561706 DOI: 10.1128/iai.02725-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Uropathogenic strains of Escherichia coli (UPEC) are the major cause of bacteremic urinary tract infections. Survival in the bloodstream is associated with different mechanisms that help to resist serum complement-mediated killing. While the phenotypic heterogeneity of bacteria has been shown to influence antibiotic tolerance, the possibility that it makes cells refractory to killing by the immune system has not been experimentally tested. In the present study we sought to determine whether the heterogeneity of bacterial cultures is relevant to bacterial targeting by the serum complement system. We monitored cell divisions in the UPEC strain CFT073 with fluorescent reporter protein. Stationary-phase cells were incubated in active or heat-inactivated human serum in the presence or absence of different antibiotics (ampicillin, norfloxacin, and amikacin), and cell division and complement protein C3 binding were measured by flow cytometry and immunofluorescence microscopy. Heterogeneity in the doubling times of CFT073 cells in serum enabled three phenotypically different subpopulations to be distinguished, all of them being recognized by the C3 component of the complement system. The population of rapidly growing cells resists serum complement-mediated lysis. The dominant subpopulation of cells with intermediate growth rate is susceptible to serum. The third population, which does not resume growth upon dilution from stationary phase, is simultaneously protected from serum complement and antibiotics.
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30
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Miajlovic H, Smith SG. Bacterial self-defence: how Escherichia coli evades serum killing. FEMS Microbiol Lett 2014; 354:1-9. [PMID: 24617921 DOI: 10.1111/1574-6968.12419] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 12/19/2022] Open
Abstract
The ability to survive the bactericidal action of serum is advantageous to extraintestinal pathogenic Escherichia coli that gain access to the bloodstream. Evasion of the innate defences present in serum, including complement and antimicrobial peptides, involves multiple factors. Serum resistance mechanisms utilized by E. coli include the production of protective extracellular polysaccharide capsules and expression of factors that inhibit or interfere with the complement cascade. Recent studies have also highlighted the importance of structural integrity of the cell envelope in serum survival. These survival strategies are outlined in this review with particular attention to novel findings and recent insights into well-established resistance mechanisms.
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Affiliation(s)
- Helen Miajlovic
- Department of Clinical Microbiology, Sir Patrick Dun Research Laboratory, School of Medicine, Trinity College, Dublin, Ireland
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31
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Gonçalves A, Poeta P, Monteiro R, Marinho C, Silva N, Guerra A, Petrucci-Fonseca F, Rodrigues J, Torres C, Vitorino R, Domingues P, Igrejas G. Comparative proteomics of an extended spectrum β-lactamase producing Escherichia coli strain from the Iberian wolf. J Proteomics 2014; 104:80-93. [PMID: 24631823 DOI: 10.1016/j.jprot.2014.02.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/15/2014] [Accepted: 02/25/2014] [Indexed: 12/13/2022]
Abstract
UNLABELLED The Iberian wolf (Canis lupus signatus) is an endangered species native to the Iberian Peninsula. Due to their predatory and wild nature, these wolves serve as important indicators of environmental contamination by antimicrobial-resistant bacteria. β-Lactam antibiotics like cefotaxime are the most commonly used antibacterial agents. Bacterial resistance to these antibiotics occurs predominantly through enzymatic inactivation by extended-spectrum beta-lactamases. Escherichia coli strain WA57, isolated from Iberian wolf feces, is a cefotaxime-resistant strain that produces extended-spectrum beta-lactamases. In this study, using 2D-GE combined with MS and bioinformatics, we report significant differences in the abundance of 40 protein spots (p<0.01) from the extracellular, periplasmic, cytoplasmic, and membrane sub-proteomes and the whole-cell proteome of WA57 exposed and non-exposed to cefotaxime. A total of 315 protein spots were collected for protein identification. The comparative proteomics presented gives an overview of the complex changes in expression and metabolism that occur when WA57 is stressed with cefotaxime. Abundance of chaperone, porin and export proteins is particularly affected showing that the stress response and transport functions might directly influence the antibiotic resistance of this strain. BIOLOGICAL SIGNIFICANCE This study highlights the importance of proteomics in detecting protein expression changes in bacterial strains exposed to stress such as that caused by cefotaxime. This approach might help us understand which pathways form barriers for antibiotics. This article is part of a Special Issue entitled: Environmental and structural proteomics.
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Affiliation(s)
- A Gonçalves
- Institute for Biotechnology and Bioengineering, Center of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Center for Animal Science and Veterinary, Vila Real, Portugal; Department of Veterinary Science, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - P Poeta
- Center for Animal Science and Veterinary, Vila Real, Portugal; Department of Veterinary Science, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - R Monteiro
- Institute for Biotechnology and Bioengineering, Center of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Center for Animal Science and Veterinary, Vila Real, Portugal; Department of Veterinary Science, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - C Marinho
- Institute for Biotechnology and Bioengineering, Center of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Center for Animal Science and Veterinary, Vila Real, Portugal; Department of Veterinary Science, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - N Silva
- Center for Animal Science and Veterinary, Vila Real, Portugal
| | - A Guerra
- Department of Animal Biology, Centre for Environmental Biology, Faculty of Sciences, University of Lisbon, Lisboa, Portugal
| | - F Petrucci-Fonseca
- Department of Animal Biology, Centre for Environmental Biology, Faculty of Sciences, University of Lisbon, Lisboa, Portugal
| | - J Rodrigues
- Center for Animal Science and Veterinary, Vila Real, Portugal; Department of Veterinary Science, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - C Torres
- Área de Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain
| | - R Vitorino
- Chemistry Department, University of Aveiro, Aveiro, Portugal
| | - P Domingues
- Chemistry Department, University of Aveiro, Aveiro, Portugal
| | - G Igrejas
- Institute for Biotechnology and Bioengineering, Center of Genomics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal; Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
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32
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Outer membrane protein P5 is required for resistance of nontypeable Haemophilus influenzae to both the classical and alternative complement pathways. Infect Immun 2013; 82:640-9. [PMID: 24478079 DOI: 10.1128/iai.01224-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The complement system is an important first line of defense against the human pathogen Haemophilus influenzae. To survive and propagate in vivo, H. influenzae has evolved mechanisms for subverting this host defense, most of which have been shown to involve outer surface structures, including lipooligosaccharide glycans and outer surface proteins. Bacterial defense against complement acts at multiple steps in the pathway by mechanisms that are not fully understood. Here we identify outer membrane protein P5 as an essential factor in serum resistance of both H. influenzae strain Rd and nontypeable H. influenzae (NTHi) clinical isolate NT127. P5 was essential for resistance of Rd and NT127 to complement in pooled human serum. Further investigation determined that P5 expression decreased cell surface binding of IgM, a potent activator of the classical pathway of complement, to both Rd and NT127. Additionally, P5 expression was required for NT127 to bind factor H (fH), an important inhibitor of alternative pathway (AP) activation. Collectively, the results obtained in this work highlight the ability of H. influenzae to utilize a single protein to perform multiple protective functions for evading host immunity.
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33
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Cisowska A, Bugla-Płoskońska G. Analysis of the SDS-PAGE patterns of outer membrane proteins from Escherichia coli strains that have lost the ability to form K1 antigen and varied in the susceptibility to normal human serum. Folia Microbiol (Praha) 2013; 59:37-43. [PMID: 23794053 PMCID: PMC3889503 DOI: 10.1007/s12223-013-0262-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 05/30/2013] [Indexed: 11/28/2022]
Abstract
We used SDS-polyacrylamide gel electrophoresis to investigate the outer membrane proteins (OMPs) band composition of 19 Escherichia coli K1 strains that have spontaneously lost the ability to form K1 polysaccharide capsule (E. coli K1-) and demonstrated different degrees of susceptibility to the bactericidal action of normal human serum. Presented results showed that there were differences between E. coli K1- strains in OMPs expressing capacity. The analysis performed on OMPs has not revealed a direct association between the different OMPs band composition and the susceptibility of these strains to the serum.
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Affiliation(s)
- Agnieszka Cisowska
- Department of Biology and Medical Parasitology, Wroclaw Medical University, Mikulicza-Radeckiego 9, 50-367, Wrocław, Poland,
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34
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Shastri A, Bonifati DM, Kishore U. Innate immunity and neuroinflammation. Mediators Inflamm 2013; 2013:342931. [PMID: 23843682 PMCID: PMC3697414 DOI: 10.1155/2013/342931] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/15/2013] [Indexed: 01/07/2023] Open
Abstract
Inflammation of central nervous system (CNS) is usually associated with trauma and infection. Neuroinflammation occurs in close relation to trauma, infection, and neurodegenerative diseases. Low-level neuroinflammation is considered to have beneficial effects whereas chronic neuroinflammation can be harmful. Innate immune system consisting of pattern-recognition receptors, macrophages, and complement system plays a key role in CNS homeostasis following injury and infection. Here, we discuss how innate immune components can also contribute to neuroinflammation and neurodegeneration.
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Affiliation(s)
- Abhishek Shastri
- Centre for Infection, Immunity and Disease Mechanisms, Heinz Wolff Building, Brunel University, London UB8 3PH, UK
| | - Domenico Marco Bonifati
- Unit of Neurology, Department of Neurological Disorders, Santa Chiara Hospital, Largo Medaglie d'oro 1, 38100 Trento, Italy
| | - Uday Kishore
- Centre for Infection, Immunity and Disease Mechanisms, Heinz Wolff Building, Brunel University, London UB8 3PH, UK
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35
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Potempa M, Potempa J. Protease-dependent mechanisms of complement evasion by bacterial pathogens. Biol Chem 2013; 393:873-88. [PMID: 22944688 DOI: 10.1515/hsz-2012-0174] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/06/2012] [Indexed: 12/11/2022]
Abstract
The human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. As the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. All successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. One of the ways in which pathogens achieve this is the deployment of proteases. Based on the increasing number of recent publications in this area, it appears that proteolytic inactivation of the antibacterial activities of the complement system is a common strategy of avoiding targeting by this arm of host innate immune defense. In this review, we focus on those bacteria that deploy proteases capable of degrading complement system components into non-functional fragments, thus impairing complement-dependent antibacterial activity and facilitating pathogen survival inside the host.
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Affiliation(s)
- Michal Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.
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Loss of outer membrane protein C in Escherichia coli contributes to both antibiotic resistance and escaping antibody-dependent bactericidal activity. Infect Immun 2012; 80:1815-22. [PMID: 22354022 DOI: 10.1128/iai.06395-11] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Outer membrane proteins (OMPs) serve as the permeability channels for nutrients, toxins, and antibiotics. In Escherichia coli, OmpA has been shown to be involved in bacterial virulence, and OmpC is related to multidrug resistance. However, it is unclear whether OmpC also has a role in the virulence of E. coli. The aims of this study were to characterize the role of OmpC in antimicrobial resistance and bacterial virulence in E. coli. The ompC deletion mutant showed significantly decreased susceptibility to carbapenems and cefepime. To investigate the survival of E. coli exposed to the innate immune system, a human blood bactericidal assay showed that the ompC mutant increased survival in blood and serum but not in complement-inactivated serum. These effects were also demonstrated in the natural selection of OmpC mutants. Also, C1q interacted with E. coli through a complex of antibodies bound to OmpC as a major target. Bacterial survival was increased in the wild-type strain in a dose-dependent manner by adding free recombinant OmpC protein or anti-C1q antibody to human serum. These results demonstrated that the interaction of OmpC-specific antibody and C1q was the key step in initiating the antibody-dependent classical pathway for the clearance of OmpC-expressing E. coli. Anti-OmpC antibody was detected in human sera, indicating that OmpC is an immunogen. These data indicate that the loss of OmpC in E. coli is resistant to not only antibiotics, but also the serum bactericidal effect, which is mediated from the C1q and anti-OmpC antibody-dependent classical pathway.
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Complement regulator C4BP binds to Staphylococcus aureus and decreases opsonization. Mol Immunol 2012; 50:253-61. [PMID: 22333221 DOI: 10.1016/j.molimm.2012.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/24/2012] [Accepted: 01/26/2012] [Indexed: 11/21/2022]
Abstract
Staphylococcus aureus is the major cause of human skin and soft-tissue infections as well as invasive infections like post-operative wound infections, septic arthritis, and osteomyelitis. The complement system plays an important role in the immunological control of many bacteria, but can be inhibited by a variety of strategies including recruitment of complement regulatory proteins like C4b-binding protein (C4BP). These experiments demonstrate that S. aureus opsonization with C4b occurs rapidly in serum and is predominantly initiated by anti-staphylococcal antibodies. Much of the S. aureus-bound C4b is quickly cleaved to the inactive forms iC4b and C4d. Clinical S. aureus strains rapidly bind significant amounts of the complement regulator C4BP from serum. S. aureus also binds purified C4BP. S. aureus-bound C4BP functions as a cofactor for factor I-mediated C4b cleavage to iC4b and C4d. In the absence of factor I, C4BP decreases classical pathway-mediated deposition of C3b on the S. aureus surface by inhibiting the classical pathway C3-convertase. In summary, C4BP is recruited to the S. aureus surface where it functions to inhibit C4 complement effectors, suggesting a previously undescribed immune evasion strategy for this pathogen.
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Krishnan S, Prasadarao NV. Outer membrane protein A and OprF: versatile roles in Gram-negative bacterial infections. FEBS J 2012; 279:919-31. [PMID: 22240162 DOI: 10.1111/j.1742-4658.2012.08482.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Outer membrane protein A (OmpA) is an abundant protein of Escherichia coli and other enterobacteria and has a multitude of functions. Although the structural features and porin function of OmpA have been well studied, its role in the pathogenesis of various bacterial infections has emerged only during the last decade. The four extracellular loops of OmpA interact with a variety of host tissues for adhesion to and invasion of the cell and for evasion of host-defense mechanisms when inside the cell. This review describes how various regions present in the extracellular loops of OmpA contribute to the pathogenesis of neonatal meningitis induced by E. coli K1 and to many other functions. In addition, the function of OmpA-like proteins, such as OprF of Pseudomonas aeruginosa, is discussed.
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Affiliation(s)
- Subramanian Krishnan
- Division of Infectious Diseases, Department of Pediatrics, The Saban Research Institute, Children's Hospital Los Angeles, CA, USA
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After genomics, what proteomics tools could help us understand the antimicrobial resistance of Escherichia coli? J Proteomics 2012; 75:2773-89. [PMID: 22245553 DOI: 10.1016/j.jprot.2011.12.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 12/30/2022]
Abstract
Proteomic approaches have been considerably improved during the past decade and have been used to investigate the differences in protein expression profiles of cells grown under a broad spectrum of growth conditions and with different stress factors including antibiotics. In Europe, the most significant disease threat remains the presence of microorganisms that have become resistant to antimicrobials and so it is important that different scientific tools are combined to achieve the largest amount of knowledge in this area of expertise. The emergence and spread of the antibiotic-resistant Gram-negative pathogens, such as Escherichia coli, can lead to serious problem public health in humans. E. coli, a very well described prokaryote, has served as a model organism for several biological and biotechnological studies increasingly so since the completion of the E. coli genome-sequencing project. The purpose of this review is to present an overview of the different proteomic approaches to antimicrobial-resistant E. coli that will be helpful to obtain a better knowledge of the antibiotic-resistant mechanism(s). This can also aid to understand the molecular determinants involved with pathogenesis, which is essential for the development of effective strategies to combat infection and to reveal new therapeutic targets. This article is part of a Special Issue entitled: Proteomics: The clinical link.
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40
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Azevedo Feitosa Ferro T, Costa Moraes F, Meneses da Silva A, Porcy C, Amorim Soares L, Andrade Monteiro C, Thyara Melo Lobão N, Amazonas Assis de Mello F, Monteiro-Neto V, de Maria Silva Figueirêdo P. Characterization of Virulence Factors in Enteroaggregative and Atypical Enteropathogenic <i>Escherichia coli</i> Strains Isolated from Children with Diarrhea. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/aid.2012.24022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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41
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Santos KV, Carvalho MAR, Martins WA, Andrade HM, Veloso LC, Coutinho SC, Bahia JL, Andrade JPL, Apolonio ACM, Diniz CG, Nicoli JR, Farias LM. Phenotypic changes in a laboratory-derived ertapenem-resistant Escherichia coli strain. J Chemother 2011; 23:135-9. [PMID: 21742581 DOI: 10.1179/joc.2011.23.3.135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The aim of this study was to identify phenotypic changes in a laboratory-derived strain of ertapenem-resistant Escherichia coli (Ec-ERT) when compared to its susceptible parent strain (Ec-WT). In both strains, we assessed both the effects of ertapenem via time-kill curves and the occurrence of cross resistance with other beta-lactams. The strains were compared based on growth pattern, biochemical-physiological profile and changes in the subproteome using 2D-DIGE followed by MALDI-TOF/TOF MS. To assess virulence, we employed a murine model of intraperitoneal infection in which we investigated the invasiveness of both strains. Growth persistence of the laboratory-derived resistant strain was observed via the time-kill curve assay, but cross resistance was not observed for other beta-lactams. We also observed a slower growth rate and changes in the biochemical and physiological characteristics of the drug-resistant bacteria. In the resistant strain, a total of 51 protein spots were increased in abundance relative to the wild-type strain, including an outer membrane protein A, which is related to bacterial virulence. The mouse infection assay showed a higher invasiveness of the Ec-ERT strain in relation to the Ec-WT strain. In conclusion, the alterations driven by ertapenem in E. coli reinforce the idea that antimicrobial agents may interfere in several aspects of bacterial cell biology, with possible implications for host-bacteria interactions.
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Affiliation(s)
- K V Santos
- Departamento de Patologia, Centro de Cièncias da Saúde, Universidade Federal do Espirito Santo, Vitória, ES, Brazil
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42
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Alteri CJ, Lindner JR, Reiss DJ, Smith SN, Mobley HL. The broadly conserved regulator PhoP links pathogen virulence and membrane potential in Escherichia coli. Mol Microbiol 2011; 82:145-63. [PMID: 21854465 PMCID: PMC3188958 DOI: 10.1111/j.1365-2958.2011.07804.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PhoP is considered a virulence regulator despite being conserved in both pathogenic and non-pathogenic Enterobacteriaceae. While Escherichia coli strains represent non-pathogenic commensal isolates and numerous virulent pathotypes, the PhoP virulence regulator has only been studied in commensal E. coli. To better understand how conserved transcription factors contribute to virulence, we characterized PhoP in pathogenic E. coli. Deletion of phoP significantly attenuated E. coli during extraintestinal infection. This was not surprising since we demonstrated that PhoP differentially regulated the transcription of > 600 genes. In addition to survival at acidic pH and resistance to polymyxin, PhoP was required for repression of motility and oxygen-independent changes in the expression of primary dehydrogenase and terminal reductase respiratory chain components. All phenotypes have in common a reliance on an energized membrane. Thus, we hypothesized that PhoP mediates these effects by regulating genes encoding proteins that generate proton motive force. Indeed, bacteria lacking PhoP exhibited a hyperpolarized membrane and dissipation of the transmembrane electrochemical gradient increased susceptibility of the phoP mutant to acidic pH, while inhibiting respiratory generation of the proton gradient restored resistance to antimicrobial peptides independent of lipopolysaccharide modification. These findings demonstrate a connection between PhoP, virulence and the energized state of the membrane.
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Affiliation(s)
- Christopher J. Alteri
- Department of Microbiology and Immunology, University of Michigan Medical School, 5641 West Medical Center Drive, Ann Arbor, Michigan 48109
| | - Jonathon R. Lindner
- Department of Microbiology and Immunology, University of Michigan Medical School, 5641 West Medical Center Drive, Ann Arbor, Michigan 48109
| | - Daniel J. Reiss
- Department of Microbiology and Immunology, University of Michigan Medical School, 5641 West Medical Center Drive, Ann Arbor, Michigan 48109
| | - Sara N. Smith
- Department of Microbiology and Immunology, University of Michigan Medical School, 5641 West Medical Center Drive, Ann Arbor, Michigan 48109
| | - Harry L.T. Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, 5641 West Medical Center Drive, Ann Arbor, Michigan 48109
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Veerhuis R, Nielsen HM, Tenner AJ. Complement in the brain. Mol Immunol 2011; 48:1592-603. [PMID: 21546088 DOI: 10.1016/j.molimm.2011.04.003] [Citation(s) in RCA: 293] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 04/04/2011] [Accepted: 04/04/2011] [Indexed: 01/24/2023]
Abstract
The brain is considered to be an immune privileged site, because the blood-brain barrier limits entry of blood borne cells and proteins into the central nervous system (CNS). As a result, the detection and clearance of invading microorganisms and senescent cells as well as surplus neurotransmitters, aged and glycated proteins, in order to maintain a healthy environment for neuronal and glial cells, is largely confined to the innate immune system. In recent years it has become clear that many factors of innate immunity are expressed throughout the brain. Neuronal and glial cells express Toll like receptors as well as complement receptors, and virtually all complement components can be locally produced in the brain, often in response to injury or developmental cues. However, as inflammatory reactions could interfere with proper functioning of the brain, tight and fine tuned regulatory mechanisms are warranted. In age related diseases, such as Alzheimer's disease (AD), accumulating amyloid proteins elicit complement activation and a local, chronic inflammatory response that leads to attraction and activation of glial cells that, under such activation conditions, can produce neurotoxic substances, including pro-inflammatory cytokines and oxygen radicals. This process may be exacerbated by a disturbed balance between complement activators and complement regulatory proteins such as occurs in AD, as the local synthesis of these proteins is differentially regulated by pro-inflammatory cytokines. Much knowledge about the role of complement in neurodegenerative diseases has been derived from animal studies with transgenic overexpressing or knockout mice for specific complement factors or receptors. These studies have provided insight into the potential therapeutic use of complement regulators and complement receptor antagonists in chronic neurodegenerative diseases as well as in acute conditions, such as stroke. Interestingly, recent animal studies have also indicated that complement activation products are involved in brain development and synapse formation. Not only are these findings important for the understanding of how brain development and neural network formation is organized, it may also give insights into the role of complement in processes of neurodegeneration and neuroprotection in the injured or aged and diseased adult central nervous system, and thus aid in identifying novel and specific targets for therapeutic intervention.
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Affiliation(s)
- Robert Veerhuis
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands.
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Mittal R, Krishnan S, Gonzalez-Gomez I, Prasadarao NV. Deciphering the roles of outer membrane protein A extracellular loops in the pathogenesis of Escherichia coli K1 meningitis. J Biol Chem 2011; 286:2183-93. [PMID: 21071448 PMCID: PMC3023514 DOI: 10.1074/jbc.m110.178236] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 10/05/2010] [Indexed: 11/06/2022] Open
Abstract
Outer membrane protein A (OmpA) has been implicated as an important virulence factor in several gram-negative bacterial infections such as Escherichia coli K1, a leading cause of neonatal meningitis associated with significant mortality and morbidity. In this study, we generated E. coli K1 mutants that express OmpA in which three or four amino acids from various extracellular loops were changed to alanines, and we examined their ability to survive in several immune cells. We observed that loop regions 1 and 2 play an important role in the survival of E. coli K1 inside neutrophils and dendritic cells, and loop regions 1 and 3 are needed for survival in macrophages. Concomitantly, E. coli K1 mutants expressing loop 1 and 2 mutations were unable to cause meningitis in a newborn mouse model. Of note, mutations in loop 4 of OmpA enhance the severity of the pathogenesis by allowing the pathogen to survive better in circulation and to produce high bacteremia levels. These results demonstrate, for the first time, the roles played by different regions of extracellular loops of OmpA of E. coli K1 in the pathogenesis of meningitis and may help in designing effective preventive strategies against this deadly disease.
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Affiliation(s)
- Rahul Mittal
- From the Division of Infectious Diseases, Department of Pediatrics, and
| | | | | | - Nemani V. Prasadarao
- From the Division of Infectious Diseases, Department of Pediatrics, and
- Surgery
- Saban Research Institute, Childrens Hospital Los Angeles and Keck School of Medicine, University of Southern California, Los Angeles, California 90027
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45
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Mittal R, Sukumaran SK, Selvaraj SK, Wooster DG, Babu MM, Schreiber AD, Verbeek JS, Prasadarao NV. Fcγ receptor I alpha chain (CD64) expression in macrophages is critical for the onset of meningitis by Escherichia coli K1. PLoS Pathog 2010; 6:e1001203. [PMID: 21124939 PMCID: PMC2987830 DOI: 10.1371/journal.ppat.1001203] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 10/21/2010] [Indexed: 11/18/2022] Open
Abstract
Neonatal meningitis due to Escherichia coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The lack of a comprehensive understanding of the mechanisms involved in the development of meningitis contributes to this poor outcome. Here, we demonstrate that depletion of macrophages in newborn mice renders the animals resistant to E. coli K1 induced meningitis. The entry of E. coli K1 into macrophages requires the interaction of outer membrane protein A (OmpA) of E. coli K1 with the alpha chain of Fcγ receptor I (FcγRIa, CD64) for which IgG opsonization is not necessary. Overexpression of full-length but not C-terminal truncated FcγRIa in COS-1 cells permits E. coli K1 to enter the cells. Moreover, OmpA binding to FcγRIa prevents the recruitment of the γ-chain and induces a different pattern of tyrosine phosphorylation of macrophage proteins compared to IgG2a induced phosphorylation. Of note, FcγRIa−/− mice are resistant to E. coli infection due to accelerated clearance of bacteria from circulation, which in turn was the result of increased expression of CR3 on macrophages. Reintroduction of human FcγRIa in mouse FcγRIa−/− macrophages in vitro increased bacterial survival by suppressing the expression of CR3. Adoptive transfer of wild type macrophages into FcγRIa−/− mice restored susceptibility to E. coli infection. Together, these results show that the interaction of FcγRI alpha chain with OmpA plays a key role in the development of neonatal meningitis by E. coli K1. Escherichia coli K1 is the most common cause of meningitis in premature infants; the mortality rate of this disease ranges from 5% to 30%. A better understanding of the pathogenesis of E. coli K1 meningitis is needed to develop new preventative strategies. We have shown that outer membrane protein A (OmpA) of E. coli K1, independent of antibody opsonization, is critical for bacterial entrance and survival within macrophages. Using a newborn mouse model, we found that depletion of macrophages renders the animals resistant to E. coli K1 induced meningitis. OmpA binds to α-chain of Fcγ-receptor I (FcγRIa) in macrophages, but does not induce expected gamma chain association and signaling. FcγRIa knockout mice are resistant to E. coli K1 infection because their macrophages express more CR3 and are thus able to kill bacteria with greater efficiency, preventing the development of high-grade bacteremia, a pre-requisite for the onset of meningitis. These novel observations demonstrate that inhibiting OmpA binding to FcγRIa is a promising therapeutic target for treatment or prevention of neonatal meningitis.
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MESH Headings
- Animals
- Animals, Newborn
- Bacterial Outer Membrane Proteins/metabolism
- Binding, Competitive
- Blotting, Western
- Brain/immunology
- Brain/metabolism
- Brain/microbiology
- COS Cells
- Chlorocebus aethiops
- Escherichia coli/growth & development
- Escherichia coli/pathogenicity
- Flow Cytometry
- Humans
- Immunoglobulin G/immunology
- Immunoglobulin G/metabolism
- Immunoprecipitation
- Macrophage-1 Antigen/metabolism
- Macrophages/immunology
- Macrophages/metabolism
- Macrophages/microbiology
- Meningitis, Escherichia coli/etiology
- Meningitis, Escherichia coli/metabolism
- Meningitis, Escherichia coli/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide/metabolism
- Phagocytosis
- Phosphorylation
- RNA, Messenger/genetics
- Receptors, IgG/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Rahul Mittal
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Sunil K. Sukumaran
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Suresh K. Selvaraj
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - David G. Wooster
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - M. Madan Babu
- Structural Studies Division, Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alan D. Schreiber
- Hematology and Oncology Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - J. Sjef Verbeek
- Department of Human Genetics, University Medical Center, Leiden, Netherlands
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
- Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Mittal R, Gonzalez-Gomez I, Panigrahy A, Goth K, Bonnet R, Prasadarao NV. IL-10 administration reduces PGE-2 levels and promotes CR3-mediated clearance of Escherichia coli K1 by phagocytes in meningitis. ACTA ACUST UNITED AC 2010; 207:1307-19. [PMID: 20498022 PMCID: PMC2882833 DOI: 10.1084/jem.20092265] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Ineffectiveness of antibiotics in treating neonatal Escherichia coli K1 meningitis and the emergence of antibiotic-resistant strains evidently warrants new prevention strategies. We observed that administration of interleukin (IL)-10 during high-grade bacteremia clears antibiotic-sensitive and -resistant E. coli from blood of infected mice. Micro-CT studies of brains from infected animals displayed gross morphological changes similar to those observed in infected human neonates. In mice, IL-10, but not antibiotic or anti-TNF antibody treatment prevented brain damage caused by E. coli. IL-10 administration elevated CR3 expression in neutrophils and macrophages of infected mice, whereas infected and untreated mice displayed increased expression of FcγRI and TLR2. Neutrophils or macrophages pretreated with IL-10 ex vivo exhibited a significantly greater microbicidal activity against E. coli compared with cells isolated from wild-type or IL-10−/− mice. The protective effect of IL-10 was abrogated when CR3 was knocked-down in vivo by siRNA. The increased expression of CR3 in phagocytes was caused by inhibition of prostaglandin E-2 (PGE-2) levels, which were significantly increased in neutrophils and macrophages upon E. coli infection. These findings describe a novel modality of IL-10–mediated E. coli clearance by diverting the entry of bacteria via CR3 and preventing PGE-2 formation in neonatal meningitis.
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Affiliation(s)
- Rahul Mittal
- Division of Infectious Diseases, Department of Pathology, Childrens Hospital Los Angeles and University of Southern California Keck School of Medicine, Los Angeles, CA 90027, USA
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47
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Valéria dos Santos K, Diniz CG, de Castro Veloso L, Monteiro de Andrade H, da Silva Giusta M, da Fonseca Pires S, Santos AV, Morais Apolônio AC, Roque de Carvalho MA, de Macêdo Farias L. Proteomic analysis of Escherichia coli with experimentally induced resistance to piperacillin/tazobactam. Res Microbiol 2010; 161:268-75. [DOI: 10.1016/j.resmic.2010.03.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/14/2010] [Accepted: 03/17/2010] [Indexed: 11/30/2022]
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48
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Zhang Y, Bao L, Zhu H, Huang B, Zhang H. OmpA-like protein Loa22 from Leptospira interrogans serovar Lai is cytotoxic to cultured rat renal cells and promotes inflammatory responses. Acta Biochim Biophys Sin (Shanghai) 2010; 42:70-9. [PMID: 20043049 DOI: 10.1093/abbs/gmp109] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Leptospirosis renal disease is one of the common clinical manifestations of leptospirosis, including acute renal failure and tubulointerstitial nephritis. Outer membrane protein A-like protein Loa22 is a lipoprotein from Leptospira interrogans and has been suggested to be a corresponding virulence factor. However, the role of Loa22 in leptospiral nephropathy is not yet understood. In the present study, we constructed a vector and artificially expressed Loa22 in Escherichia coli BL21(DE)pLysS cells. After extensive purification, along with a GST tag protein control, Loa22 protein was used to test the cytotoxicity in cultured rat proximal tubule cells (NRK52E) and examine its effects on the induction of inflammatory responses. Using morphological examination, 2,3-bis(2-methoxy-4- nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazoium hydrixide absorbance, lactate dehydrogenase assays and an analysis of apoptosis via flow cytometry, it was found that Loa22 protein mediates a direct cytotoxic effect on NRK52E cells in a dose-dependent manner. Using real-time PCR, western blotting and immunofluorescence, it was found that Loa22 protein upregulates the expression of toll-like receptor 2 (TLR2), induces nitric oxide synthase and promotes the production of nitric oxide (NO) and monocyte chemoattractant protein-1 (MCP-1) by NRK52E cells. Additionally, using a TLR2 blocking antibody, it was found that enhanced NO and MCP-1 production by NRK52E cells after Loa22 stimulation requires the activation of TLR2. Collectively, our data suggested that Loa22 is a critical virulence factor of L. interrogans and is involved in the leptospiral nephropathy through mediating direct cytotoxicity and enhancing inflammatory responses.
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Affiliation(s)
- Ying Zhang
- Infection and Immunity Lab, West China Medical Center, Sichuan University, Chengdu, China.
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49
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Croxen MA, Finlay BB. Molecular mechanisms of Escherichia coli pathogenicity. Nat Rev Microbiol 2009; 8:26-38. [DOI: 10.1038/nrmicro2265] [Citation(s) in RCA: 668] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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50
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Complement evasion strategies of pathogens-acquisition of inhibitors and beyond. Mol Immunol 2009; 46:2808-17. [PMID: 19477524 DOI: 10.1016/j.molimm.2009.04.025] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 04/28/2009] [Indexed: 12/31/2022]
Abstract
Activation of the complement system and resulting opsonisation with C3b are key events of the innate immune defense against infections. However, a wide variety of bacterial pathogens subvert complement attack by binding host complement inhibitors such as C4b-binding protein, factor H and vitronectin, which results in diminished opsonophagocytosis and killing of bacteria by lysis. Another widely used strategy is production of proteases, which can effectively degrade crucial complement components. Furthermore, bacterial pathogens such as Moraxella catarrhalis and Staphylococcus aureus capture and incapacitate the key complement component C3. The current review describes examples of these three strategies. Targeting binding sites for complement inhibitors on bacterial surfaces and complement-degrading proteases with vaccine-induced antibodies may be used to enhance a common vaccine design strategy that depends on the generation of complement-dependent bactericidal and opsonophagocytic antibody activities.
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