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Almeida JR, Palacios ALV, Patiño RSP, Mendes B, Teixeira CAS, Gomes P, da Silva SL. Harnessing snake venom phospholipases A 2 to novel approaches for overcoming antibiotic resistance. Drug Dev Res 2018; 80:68-85. [PMID: 30255943 DOI: 10.1002/ddr.21456] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/25/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022]
Abstract
The emergence of antibiotic resistance drives an essential race against time to reveal new molecular structures capable of addressing this alarming global health problem. Snake venoms are natural catalogs of multifunctional toxins and privileged frameworks, which serve as potential templates for the inspiration of novel treatment strategies for combating antibiotic resistant bacteria. Phospholipases A2 (PLA2 s) are one of the main classes of antibacterial biomolecules, with recognized therapeutic value, found in these valuable secretions. Recently, a number of biomimetic oligopeptides based on small fragments of primary structure from PLA2 toxins has emerged as a meaningful opportunity to overcome multidrug-resistant clinical isolates. Thus, this review will highlight the biochemical and structural properties of antibacterial PLA2 s and peptides thereof, as well as their possible molecular mechanisms of action and key roles in development of effective therapeutic strategies. Chemical strategies possibly useful to convert antibacterial peptides from PLA2 s to efficient drugs will be equally addressed.
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Affiliation(s)
| | | | | | - Bruno Mendes
- Departamento de Biologia Animal, Instituto de Biologia, Universidade de Campinas (UNICAMP), Campinas, Brazil
| | - Cátia A S Teixeira
- LAQV/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Paula Gomes
- LAQV/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Saulo L da Silva
- Facultad de Ciencias Química, Universidad de Cuenca - Cuenca/Azuay - Ecuador
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2
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Grange PA, Raingeaud J, Morelle W, Marcelin AG, Calvez V, Dupin N. Characterization of a Propionibacterium acnes Surface Protein as a Fibrinogen-Binding Protein. Sci Rep 2017; 7:6428. [PMID: 28743910 PMCID: PMC5527093 DOI: 10.1038/s41598-017-06940-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/26/2017] [Indexed: 12/28/2022] Open
Abstract
Propionibacterium acnes (P. acnes) is a major skin-associated bacterium that was long considered commensal, until several studies revealed it to be an opportunistic pathogen. We investigated the ability of P. acnes surface proteins to recognize ECM proteins and showed that a 58 kDa P. acnes surface protein was specifically recognized by human fibrinogen (hFg). The 58 kDa protein was further characterized by two-dimensional (2-D) electrophoresis and MALDI-ToF as a P. acnes host cell-surface attachment protein, PA25957, recognizing dermatan sulfate (DsA1). This protein sequence contains 432 amino acids with the presence of three structurally different domains: an N-terminal signal peptide, a C-terminal LPXTG motif, and a PT repeat region. DsA1 is mostly produced during stationary phase. It appears to be highly glycosylated, containing GalNAc residues. Purified DsA1 strongly recognizes the Aα and Bβ subunits of hFg, and specific enzymatic deglycosylation of hFg demonstrated the involvement of the protein backbone in the recognition process. The Bβ subunit of hFg was cloned in four peptide fractions (Fg1-Fg4). The N-terminal Fg1 peptide of hFg was recognized by DsA1, and priming DsA1 with Fg1 inhibited DsA1/hFg recognition. We describe here for the first time, the characterization of a P. acnes surface glycoprotein recognizing human fibrinogen.
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Affiliation(s)
- Philippe A Grange
- Université Sorbonne Paris Descartes, Faculté de Médecine, INSERM CNRS UMR8104, Institut Cochin U1016, Laboratoire de Dermatologie-CNR Syphilis, Paris, France
| | | | - Willy Morelle
- UMR CNRS/USTL 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Université des Science et Technologies de Lille 1, Villeneuve-d'Ascq, France
| | - Anne-Geneviève Marcelin
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière - Charles Foix, Service de Virologie - INSERM 1136-UMR UPMC Paris 6, Paris, France
| | - Vincent Calvez
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière - Charles Foix, Service de Virologie - INSERM 1136-UMR UPMC Paris 6, Paris, France
| | - Nicolas Dupin
- Université Sorbonne Paris Descartes, Faculté de Médecine, INSERM CNRS UMR8104, Institut Cochin U1016, Laboratoire de Dermatologie-CNR Syphilis, Paris, France.
- AP-HP, Groupe Hospitalier Paris Centre Cochin-Hôtel Dieu-Broca, Service de Dermatologie-Vénéréologie, Paris, France.
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3
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Crosby HA, Kwiecinski J, Horswill AR. Staphylococcus aureus Aggregation and Coagulation Mechanisms, and Their Function in Host-Pathogen Interactions. ADVANCES IN APPLIED MICROBIOLOGY 2016; 96:1-41. [PMID: 27565579 DOI: 10.1016/bs.aambs.2016.07.018] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human commensal bacterium Staphylococcus aureus can cause a wide range of infections ranging from skin and soft tissue infections to invasive diseases like septicemia, endocarditis, and pneumonia. Muticellular organization almost certainly contributes to S. aureus pathogenesis mechanisms. While there has been considerable focus on biofilm formation and its role in colonizing prosthetic joints and indwelling devices, less attention has been paid to nonsurface-attached group behavior like aggregation and clumping. S. aureus is unique in its ability to coagulate blood, and it also produces multiple fibrinogen-binding proteins that facilitate clumping. Formation of clumps, which are large, tightly packed groups of cells held together by fibrin(ogen), has been demonstrated to be important for S. aureus virulence and immune evasion. Clumps of cells are able to avoid detection by the host's immune system due to a fibrin(ogen) coat that acts as a shield, and the size of the clumps facilitates evasion of phagocytosis. In addition, clumping could be an important early step in establishing infections that involve tight clusters of cells embedded in host matrix proteins, such as soft tissue abscesses and endocarditis. In this review, we discuss clumping mechanisms and regulation, as well as what is known about how clumping contributes to immune evasion.
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Affiliation(s)
- H A Crosby
- University of Iowa, Iowa City, IA, United States
| | - J Kwiecinski
- University of Iowa, Iowa City, IA, United States
| | - A R Horswill
- University of Iowa, Iowa City, IA, United States
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4
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Lee HY, Zou Y, Ahn J. Physiochemical and molecular properties of antimicrobial-exposed Staphylococcus aureus during the planktonic-to-biofilm transition. ANN MICROBIOL 2012. [DOI: 10.1007/s13213-012-0572-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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5
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Characterization of serum phospholipase a(2) activity in three diverse species of west african crocodiles. Biochem Res Int 2011; 2011:925012. [PMID: 22110960 PMCID: PMC3205705 DOI: 10.1155/2011/925012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 07/21/2011] [Accepted: 07/25/2011] [Indexed: 11/17/2022] Open
Abstract
Secretory phospholipase A(2), an enzyme that exhibits substantial immunological activity, was measured in the serum of three species of diverse West African crocodiles. Incubation of different volumes of crocodile serum with bacteria labeled with a fluorescent fatty acid in the sn-2 position of membrane lipids resulted in a volume-dependent liberation of fluorescent probe. Serum from the Nile crocodile (Crocodylus niloticus) exhibited slightly higher activity than that of the slender-snouted crocodile (Mecistops cataphractus) and the African dwarf crocodile (Osteolaemus tetraspis). Product formation was inhibited by BPB, a specific PLA(2) inhibitor, confirming that the activity was a direct result of the presence of serum PLA(2). Kinetic analysis showed that C. niloticus serum produced product more rapidly than M. cataphractus or O. tetraspis. Serum from all three species exhibited temperature-dependent PLA(2) activities but with slightly different thermal profiles. All three crocodilian species showed high levels of activity against eight different species of bacteria.
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6
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Houston S, Blakely GW, McDowell A, Martin L, Patrick S. Binding and degradation of fibrinogen by Bacteroides fragilis and characterization of a 54 kDa fibrinogen-binding protein. MICROBIOLOGY-SGM 2010; 156:2516-2526. [PMID: 20466764 DOI: 10.1099/mic.0.038588-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Bacteroides fragilis is a bacterium that resides in the normal human gastro-intestinal tract; however, it is also the most commonly isolated Gram-negative obligate anaerobe from human clinical infections, such as intra-abdominal abscesses, and the most common cause of anaerobic bacteraemia. Abscess formation is important in bacterial containment, limiting dissemination of infection and bacteraemia. In this study, we investigated B. fragilis binding and degradation of human fibrinogen, the major structural component involved in fibrin abscess formation. We have shown that B. fragilis NCTC9343 binds human fibrinogen. A putative Bacteroides fragilis fibrinogen-binding protein, designated BF-FBP, identified in the genome sequence of NCTC9343, was cloned and expressed in Escherichia coli. The purified recombinant BF-FBP bound primarily to the human fibrinogen Bbeta-chain. In addition, we have identified fibrinogenolytic activity in B. fragilis exponential phase culture supernatants, associated with fibrinogenolytic metalloproteases in NCTC9343 and 638R, and cysteine protease activity in YCH46. All nine clinical isolates of B. fragilis examined degraded human fibrinogen; with eight isolates, initial Aalpha-chain degradation was observed, with varying Bbeta-chain and gamma-chain degradation. With one blood culture isolate, Bbeta-chain and gamma-chain degradation occurred first, followed by subsequent Aalpha-chain degradation. Our data raise the possibility that the fibrinogen-binding protein of B. fragilis, along with a variety of fibrinogenolytic proteases, may be an important virulence factor that facilitates dissemination of infection via reduction or inhibition of abscess formation.
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Affiliation(s)
- Simon Houston
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Garry W Blakely
- Institute of Cell Biology, University of Edinburgh, Darwin Building, Kings Buildings, Edinburgh EH9 3JR, UK
| | - Andrew McDowell
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Lorraine Martin
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Sheila Patrick
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
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7
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Brueseke TJ, Bell JD. A new hat for an old enzyme: Waste management. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1270-9. [PMID: 16828338 DOI: 10.1016/j.bbalip.2006.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 05/19/2006] [Accepted: 05/24/2006] [Indexed: 11/27/2022]
Abstract
The history of research regarding secretory phospholipase A(2) (sPLA(2)) has often focused in one of two directions. Originally, the enzyme was studied biophysically in terms of its fundamental structure, enzymology, and the relationship between membrane physics and catalytic activity. More recently, a large and growing body of information has accumulated concerning regulatory factors, tissue distribution, and physiological/pathological roles of sPLA(2). Evidence is presented that suggests an additional function for the protein in which it helps to clear dead and damaged cells while avoiding digestion of those that are healthy. Apparently, the ability of the enzyme to discriminate between susceptible and resistant cells depends on physical properties of membrane lipids related to order, distribution, and neighbor/neighbor interactions. Investigations into this action of the enzyme offer the rare opportunity to apply biophysical approaches and principles to a physiological setting.
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Affiliation(s)
- Taylor J Brueseke
- Department of Physiology and Developmental Biology, College of Biology and Agriculture, 302C WIDB, Brigham Young University, Provo, UT 84602, USA
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8
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Menschikowski M, Hagelgans A, Siegert G. Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases? Prostaglandins Other Lipid Mediat 2006; 79:1-33. [PMID: 16516807 DOI: 10.1016/j.prostaglandins.2005.10.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/29/2005] [Accepted: 10/31/2005] [Indexed: 02/07/2023]
Abstract
Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie and Laboratoriumsmedizin, Fetscherstrasse 74, D-01307 Dresden, Germany.
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9
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Femling JK, Nauseef WM, Weiss JP. Synergy between extracellular group IIA phospholipase A2 and phagocyte NADPH oxidase in digestion of phospholipids of Staphylococcus aureus ingested by human neutrophils. THE JOURNAL OF IMMUNOLOGY 2005; 175:4653-61. [PMID: 16177112 DOI: 10.4049/jimmunol.175.7.4653] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acute inflammatory responses to invading bacteria such as Staphylococcus aureus include mobilization of polymorphonuclear leukocytes (PMN) and extracellular group IIA phospholipase A2 (gIIA-PLA2). Although accumulating coincidentally, the in vitro anti-staphylococcal activities of PMN and gIIA-PLA2 have thus far been studied separately. We now show that degradation of S. aureus phospholipids during and after phagocytosis by human PMN requires the presence of extracellular gIIA-PLA2. The concentration of extracellular gIIA-PLA2 required to produce bacterial digestion was reduced 10-fold by PMN. The effects of added gIIA-PLA2 were greater when present before phagocytosis but even apparent when added after S. aureus were ingested by PMN. Related group V and X PLA2, which are present within PMN granules, do not contribute to bacterial phospholipid degradation during and after phagocytosis even when added at concentrations 30-fold higher than that needed for action of the gIIA-PLA2. The action of added gIIA-PLA2 required catalytically active gIIA-PLA2 and, in PMN, a functional NADPH oxidase but not myeloperoxidase. These findings reveal a novel collaboration between cellular oxygen-dependent and extracellular oxygen-independent host defense systems that may be important in the ultimate resolution of S. aureus infections.
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Affiliation(s)
- Jon K Femling
- The Inflammation Program, University of Iowa and Veterans Affairs Medical Center, Iowa City 52242, USA
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10
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Villarrubia VG, Costa LA, Díez RA. [Secreted phospholipases A2 (sPLA2): friends or foes? Are they actors in antibacterial and anti-HIV resistance?]. Med Clin (Barc) 2005; 123:749-57. [PMID: 15574291 DOI: 10.1016/s0025-7753(04)74656-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this paper the authors update on the deletereous or beneficial roles of human and animal secretory phospholipases A2 (sPLA2). Although human sPLA2-IIA (inflammatory) was initially thought as a foe because its pathogenic implication in sepsis, multiorganic failure or other related syndromes, recent data indicates its role in in the antiinfectious host resistance. Thus, sPLA2-IIA exhibits potent bactericidal activities against gram-negative and gram-positive (in this case, together with other endogenous inflammatory factors) bacteria. Surprisingly, human sPLA-IIA does not show in vitro anti-human immunodeficiency virus (HIV) activity, whilst several sPLA2-IA isolated from bee and serpent venons do it: this is the case for crotoxin, a sPLA2-IA isolated from the venon of Crotalus durissus terrificus (sPLA2-Cdt). The mechanism for the in vitro anti-HIV activity of sPLA2-Cdt (inhibition of Gag p24) appears to be related to the ability of the drug to desestabilize ancorage (heparans) and fusion (cholesterol) receptors on HIV target cells.
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11
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Rothfork JM, Dessus-Babus S, Van Wamel WJB, Cheung AL, Gresham HD. Fibrinogen depletion attenuates Staphyloccocus aureus infection by preventing density-dependent virulence gene up-regulation. THE JOURNAL OF IMMUNOLOGY 2004; 171:5389-95. [PMID: 14607942 DOI: 10.4049/jimmunol.171.10.5389] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus undergoes a density-dependent conversion in phenotype from tissue-adhering to tissue-damaging and phagocyte-evading that is mediated in part by the quorum-sensing operon, agr, and its effector, RNAIII. Contributions of host factors to this mechanism for regulating virulence have not been studied. We hypothesized that fibrinogen, as a component of the inflammatory response, could create spatially constrained microenvironments around bacteria that increase density independently of bacterial numbers and thus potentiate quorum-sensing-dependent virulence gene expression. Here we show that transient fibrinogen depletion significantly reduces the bacterial burden and the consequential morbidity and mortality during experimental infection with wild-type S. aureus, but not with bacteria that lack expression of the quorum-sensing operon, agr. In addition, it inhibits in vivo activation of the promoter for the agr effector, RNAIII, and downstream targets of RNAIII, including alpha hemolysin and capsule production. Moreover, both in vitro and in vivo, the mechanism for promoting this phenotypic switch in virulence involves clumping of the bacteria, demonstrating that S. aureus responds to fibrinogen-mediated bacterial clumping by enhancing density-dependent virulence gene expression. These data demonstrate that down-modulation of specific inflammatory components of the host that augment bacterial quorum sensing can be a strategy for enhancing host defense against infection.
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Affiliation(s)
- Jacob M Rothfork
- Research Service, Albuquerque Veterans Affairs Medical Center, Albuquerque, NM 87108, USA
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12
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Yajima M, Nakayama M, Hatano S, Yamazaki K, Aoyama Y, Yajima T, Kuwata T. Bacterial translocation in neonatal rats: the relation between intestinal flora, translocated bacteria, and influence of milk. J Pediatr Gastroenterol Nutr 2001; 33:592-601. [PMID: 11740235 DOI: 10.1097/00005176-200111000-00015] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND A high incidence of bacterial translocation in neonates results not only from immaturity of host-defense functions, but also from the dominant colonization of aerobic bacteria in the intestine. Bacterial colonization develops differently among breast-fed, formula-fed, premature, and full-term infants. The purpose of this study was to examine the incidence of bacterial translocation and to identify the translocated bacterial species, relating these findings to the intestinal microflora and to the type of feeding in neonatal rats. METHODS Animals were divided into three groups: breast-fed normal pups (MR group), formula-fed pups fed via an intragastric cannula implanted esophageally (AR group), and breast-fed pups after the removal of the cannula (Sham group). Artificial rearing was achieved using a machine feeding system. Culture and identification of the bacteria in the intestine, mesenteric lymph nodes, liver, portal blood, and lungs were made using a simplified version of Mitsuoka's method. RESULTS At 14 days of age, the dominant bacteria in the feces of the MR and Sham Groups were Enterobacteriaceae, Lactobacillus, and Enterococcus, but Enterobacteriaceae and Clostridium were significantly more common in the AR group than in the MR group. The dominant bacteria in the mesenteric lymph nodes were Enterobacteriaceae, Lactobacillus, and Staphylococcus. The extent of systemic bacterial translocation decreased earlier in the Sham group than in the AR group. CONCLUSIONS The frequency with which species of bacteria were cultured from mesenteric lymph nodes and other peripheral sites did not mirror the composition of the intestinal flora. Among the translocated bacteria, Staphylococcus may be especially hard to recognize and difficult for the host-defense systems to destroy. Breast-feeding inhibited systemic bacterial translocation in the suckling period of the rat.
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Affiliation(s)
- M Yajima
- Department of Nutritional Research, Nutrition Science Institute, Meiji Milk Products Co., Ltd., 1-21-3 Sakae, Higashimurayama, Tokyo 189-8530, Japan.
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Rozenfeld RA, Liu X, DePlaen I, Hsueh W. Role of gut flora on intestinal group II phospholipase A2 activity and intestinal injury in shock. Am J Physiol Gastrointest Liver Physiol 2001; 281:G957-63. [PMID: 11557516 DOI: 10.1152/ajpgi.2001.281.4.g957] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We previously showed that group II phospholipase A2 (PLA2-II), a secretory, bactericidal, and proinflammatory protein in intestinal crypts, is upregulated after lipopolysaccharide (LPS) and platelet-activating factor (PAF) challenge. Here we examined whether germ-free environment (GF) or antibiotic treatment (ABX) affects the pathophysiological responses and intestinal PLA2-II activity after PAF (1.5 microg/kg) or LPS (8 mg/kg) injection. We found that LPS and PAF induced hypotension and mild intestinal injury in conventionally fed (CN) rats; these changes were milder in ABX rats, whereas GF rats showed no intestinal injury. PLA2-II enzyme activity was detected in normal rat small intestine; the basal level was not diminished in ABX or GF rats. PAF and LPS caused an increase in PLA2-II activity, which was abrogated in GF and ABX rats. Recolonization of GF rats by enteral contamination restituted their PLA2-II response to PAF and LPS and susceptibility to bowel injury. We conclude that PAF- and LPS-induced increases in PLA2-II activity are dependent on gut bacteria, and ABX and GF rats are less susceptible to LPS-induced injury than CN rats.
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Affiliation(s)
- R A Rozenfeld
- Department of Pediatrics, Children's Memorial Hospital, Northwestern University Medical School, Chicago, Illinois 60614, USA
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Stepanović S, Vukovicć D, Trajković V, Samardzić T, Cupić M, Svabić-Vlahović M. Possible virulence factors of Staphylococcus sciuri. FEMS Microbiol Lett 2001; 199:47-53. [PMID: 11356566 DOI: 10.1111/j.1574-6968.2001.tb10649.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Staphylococcus sciuri is an opportunistic pathogen of controversial clinical significance. The factors that contribute to colonization and/or infection caused by this bacterium have not been studied intensively so far. The present research was carried out in order to study the presence of potential virulence factors in 121 human and animal isolates of this bacterium. Isolates were examined for biofilm formation, hemagglutination, presence of clumping factor, production of spreading factors and exotoxins, cytotoxicity and capacity to stimulate nitric oxide production. The results showed that S. sciuri is highly capable of biofilm production, that it displays strong proteolytic and DNase activities, produces hemolysins and stimulates nitric oxide production by rat macrophages. Although the present study showed existence of a wide spectrum of possible virulence determinants of S. sciuri, their exact contribution to virulence of this bacterium in vivo remains to be determined.
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Affiliation(s)
- S Stepanović
- Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Yugoslavia.
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15
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Buckland AG, Wilton DC. The antibacterial properties of secreted phospholipases A(2). BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:71-82. [PMID: 11080678 DOI: 10.1016/s1388-1981(00)00111-6] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
There is a considerable body of evidence to support the antibacterial properties of the group IIa phospholipase A(2) as an important physiological function. This enzyme is able to act as an acute phase protein and may be part of the innate defence system of the body, acting in concert with other antibacterial proteins and peptides. The enzyme is most effective against Gram-positive bacteria whereas penetration of the lipopolysaccharide coat of Gram-negative bacteria requires bactericidal/permeability-increasing protein (BPI) as an additional permeabilizing factor. The global cationic nature of this protein (pI>10.5) appears to facilitate penetration of the anionic bacterial cell wall. In addition, the considerable preference of the enzyme for anionic phospholipid interfaces provides specificity toward anionic bacterial membranes as opposed to zwitterionic eucaryotic cell membranes.
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Affiliation(s)
- A G Buckland
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, Bassett Crescent East, SO16 7PX, Southampton, UK
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16
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Gresham HD, Lowrance JH, Caver TE, Wilson BS, Cheung AL, Lindberg FP. Survival of Staphylococcus aureus inside neutrophils contributes to infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:3713-22. [PMID: 10725730 DOI: 10.4049/jimmunol.164.7.3713] [Citation(s) in RCA: 335] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neutrophils have long been regarded as essential for host defense against Staphylococcus aureus infection. However, survival of the pathogen inside various cells, including phagocytes, has been proposed as a mechanism for persistence of this microorganism in certain infections. Therefore, we investigated whether survival of the pathogen inside polymorphonuclear neutrophils (PMN) contributes to the pathogenesis of S. aureus infection. Our data demonstrate that PMN isolated from the site of infection contain viable intracellular organisms and that these infected PMN are sufficient to establish infection in a naive animal. In addition, we show that limiting, but not ablating, PMN migration into the site of infection enhances host defense and that repletion of PMN, as well as promoting PMN influx by CXC chemokine administration, leads to decreased survival of the mice and an increased bacterial burden. Moreover, a global regulator mutant of S. aureus (sar-) that lacks the expression of several virulence factors is less able to survive and/or avoid clearance in the presence of PMN. These data suggest that the ability of S. aureus to exploit the inflammatory response of the host by surviving inside PMN is a virulence mechanism for this pathogen and that modulation of the inflammatory response is sufficient to significantly alter morbidity and mortality induced by S. aureus infection.
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Affiliation(s)
- H D Gresham
- Research Service, Albuquerque Veterans Affairs Medical Center, Albuquerque, NM, 87108, USA.
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Lammers A, Nuijten PJ, Smith HE. The fibronectin binding proteins of Staphylococcus aureus are required for adhesion to and invasion of bovine mammary gland cells. FEMS Microbiol Lett 1999; 180:103-9. [PMID: 10547450 DOI: 10.1111/j.1574-6968.1999.tb08783.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We recently described adhesion to and invasion of bovine mammary gland cells by Staphylococcus aureus in vitro. Here, we show that the levels of adhesion and invasion are dependent on the bacterial growth phase and are controlled by the agr locus. Incubation of exponential growth phase cells of S. aureus with mammary gland cells resulted in bacterial cell clumping. Strains of S. aureus deficient in expression of the fibronectin binding proteins (FnBPA and FnBPB) failed to clump and their ability to adhere to and to invade the bovine mammary gland cells is strongly reduced. This indicates that the fibronectin binding proteins are essential for S. aureus adhesion to and invasion of bovine mammary gland cells.
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Affiliation(s)
- A Lammers
- Department of Bacteriology, Institute for Animal Science and Health, P.O. Box 65, 8200 AB, Lelystad, The Netherlands.
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