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Javed A, Slingerland CJ, Wood TM, Martin NI, Broere F, Weingarth MH, Veldhuizen EJA. Chimeric Peptidomimetic Antibiotic Efficiently Neutralizes Lipopolysaccharides (LPS) and Bacteria-Induced Activation of RAW Macrophages. ACS Infect Dis 2023; 9:518-526. [PMID: 36790385 PMCID: PMC10012172 DOI: 10.1021/acsinfecdis.2c00518] [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: 02/16/2023]
Abstract
Peptide antibiotics have gathered attention given the urgent need to discover antimicrobials with new mechanisms of action. Their extended role as immunomodulators makes them interesting candidates for the development of compounds with dual mode of action. The objective of this study was to test the anti-inflammatory capacity of a recently reported chimeric peptidomimetic antibiotic (CPA) composed of polymyxin B nonapeptide (PMBN) and a macrocyclic β-hairpin motif (MHM). We investigated the potential of CPA to inhibit lipopolysaccharide (LPS)-induced activation of RAW264.7 macrophages. In addition, we elucidated which structural motif was responsible for this activity by testing CPA, its building blocks, and their parent compounds separately. CPA showed excellent LPS neutralizing activity for both smooth and rough LPSs. At nanomolar concentrations, CPA completely inhibited LPS-induced nitric oxide, TNF-α, and IL-10 secretion. Murepavadin, MHM, and PMBN were incapable of neutralizing LPS in this assay, while PMB was less active compared to CPA. Isothermal titration calorimetry showed strong binding between the CPA and LPS with similar binding characteristics also found for the other compounds, indicating that binding does not necessarily correlate with neutralization of LPS. Finally, we showed that CPA-killed bacteria caused significantly less macrophage activation than bacteria killed with gentamicin, heat, or any of the other compounds. This indicates that the combined killing activity and LPS neutralization of CPA can prevent unwanted inflammation, which could be a major advantage over conventional antibiotics. Our data suggests that immunomodulatory activity can further strengthen the therapeutic potential of peptide antibiotics and should be included in the characterization of novel compounds.
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Affiliation(s)
- Ali Javed
- Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Division Infectious Diseases & Immunology, Section Immunology, Utrecht University, 3584 CL Utrecht, The Netherlands.,NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Cornelis J Slingerland
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
| | - Thomas M Wood
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
| | - Nathaniel I Martin
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University, 2333 BE Leiden, The Netherlands
| | - Femke Broere
- Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Division Infectious Diseases & Immunology, Section Immunology, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Markus H Weingarth
- NMR Spectroscopy, Bijvoet Centre for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Edwin J A Veldhuizen
- Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Division Infectious Diseases & Immunology, Section Immunology, Utrecht University, 3584 CL Utrecht, The Netherlands
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2
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Interaction of Lipopolysaccharide-Spiked Blood with Anti-Fouling Polymyxin B-Modified Glass. MATERIALS 2022; 15:ma15041551. [PMID: 35208091 PMCID: PMC8876862 DOI: 10.3390/ma15041551] [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] [Received: 12/03/2021] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 11/20/2022]
Abstract
Bacterial endotoxin, also known as lipopolysaccharide (LPS), plays a major role in the initiation of sepsis, a severe inflammatory condition. Removal of the toxin from blood is one accepted method of patient treatment. Polymyxin B (PMB)-modified columns have been employed successfully for this purpose via extra-corporeal blood-flow systems that incorporate a cartridge for toxin removal. Herein we demonstrate that PMB-modified glass beads are able to reduce the presence of LPS competitively with the equivalent fiber column used in a commercial cartridge. Analysis by gas chromatography-mass spectrometry and ELISA of released fatty acids from the toxin indicates that PMB does not physically capture or significantly remove LPS from the blood samples. In reality, interaction between the surface-bound PMB and the toxin may lead to disaggregation or monomerization of LPS aggregates. As aggregates are the bioactive form of LPS, it is possible that the monomerization of these entities may be the mechanism by which their toxicity is reduced. Moreover, this work indicates that LPS monomers are stabilized subsequent to disaggregation induced by PMB.
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3
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An in vitro study on factors affecting endotoxin neutralization in human plasma using the Limulus amebocyte lysate test. Sci Rep 2021; 11:4192. [PMID: 33603020 PMCID: PMC7893160 DOI: 10.1038/s41598-021-83487-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 01/21/2021] [Indexed: 01/14/2023] Open
Abstract
Endotoxin neutralization, caused by plasma components, makes it difficult to detect endotoxins in human blood. In this study, we investigated which factors influence the recovery of endotoxins using limulus ameobocyte lysate (LAL)-based assays. The individual factors that were examined in more detail were lipoprotein content, type of blood anticoagulation, kinetics and serum levels of divalent cations. Furthermore, it was investigated whether there is a direct correlation between LAL activity and monocyte activation. We could show that polyanionic heparin increases endotoxin recovery in blood, while citrate anticoagulation promotes endotoxin neutralization. Furthermore, we could show that the endotoxin activity in human plasma and serum decreases strongly over time. Time-dependent endotoxin neutralization reaches its maximum after 4–6 h incubation. By means of filtration tests we could determine that endotoxins in the plasma bind to lipoproteins but do not influence their activity. Comparative measurements have shown that high LAL activity of endotoxins in plasma simultaneously possesses high monocyte activating properties in whole blood. For the maximum recovery of endotoxins in human blood the physiological calcium and magnesium concentrations are sufficient. In this study, it was shown that the endotoxin neutralizing plasma components have a molecular weight similar to β2-microglobulin (11.7 kDa). For the exact identification of the endotoxin neutralizing plasma components, which caused a modulation of the immunostimulating endotoxin activity, further investigations have to be carried out in the future.
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4
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Lipid-Protein and Protein-Protein Interactions in the Pulmonary Surfactant System and Their Role in Lung Homeostasis. Int J Mol Sci 2020; 21:ijms21103708. [PMID: 32466119 PMCID: PMC7279303 DOI: 10.3390/ijms21103708] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022] Open
Abstract
Pulmonary surfactant is a lipid/protein complex synthesized by the alveolar epithelium and secreted into the airspaces, where it coats and protects the large respiratory air–liquid interface. Surfactant, assembled as a complex network of membranous structures, integrates elements in charge of reducing surface tension to a minimum along the breathing cycle, thus maintaining a large surface open to gas exchange and also protecting the lung and the body from the entrance of a myriad of potentially pathogenic entities. Different molecules in the surfactant establish a multivalent crosstalk with the epithelium, the immune system and the lung microbiota, constituting a crucial platform to sustain homeostasis, under health and disease. This review summarizes some of the most important molecules and interactions within lung surfactant and how multiple lipid–protein and protein–protein interactions contribute to the proper maintenance of an operative respiratory surface.
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5
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Golpour A, Bereswill S, Heimesaat MM. Antimicrobial and Immune-Modulatory Effects of Vitamin D Provide Promising Antibiotics-Independent Approaches to Tackle Bacterial Infections - Lessons Learnt from a Literature Survey. Eur J Microbiol Immunol (Bp) 2019; 9:80-87. [PMID: 31662886 PMCID: PMC6798578 DOI: 10.1556/1886.2019.00014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 07/24/2019] [Indexed: 12/19/2022] Open
Abstract
Antimicrobial multidrug-resistance (MDR) constitutes an emerging threat to global health and makes the effective prevention and treatment of many, particularly severe infections challenging, if not impossible. Many antibiotic classes have lost antimicrobial efficacy against a plethora of infectious agents including bacterial species due to microbial acquisition of distinct resistance genes. Hence, the development of novel anti-infectious intervention strategies including antibiotic-independent approaches is urgently needed. Vitamins such as vitamin D and vitamin D derivates might be such promising molecular candidates to combat infections caused by bacteria including MDR strains. Using the Pubmed database, we therefore performed an in-depth literature survey, searching for publications on the antimicrobial effect of vitamin D directed against bacteria including MDR strains. In vitro and clinical studies between 2009 and 2019 revealed that vitamin D does, in fact, possess antimicrobial properties against both Gram-positive and Gram-negative bacterial species, whereas conflicting results could be obtained from in vivo studies. Taken together, the potential anti-infectious effects for the antibiotic-independent application of vitamin D and/or an adjunct therapy in combination with antibiotic compounds directed against infectious diseases such as tuberculosis, H. pylori infections, or skin diseases, for instance, should be considered and further investigated in more detail.
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Affiliation(s)
- Ainoosh Golpour
- Institute of Microbiology, Infectious Diseases and Immunology Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stefan Bereswill
- Institute of Microbiology, Infectious Diseases and Immunology Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Markus M Heimesaat
- Institute of Microbiology, Infectious Diseases and Immunology Charité - University Medicine Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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6
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Sali W, Patoli D, Pais de Barros JP, Labbé J, Deckert V, Duhéron V, Le Guern N, Blache D, Chaumont D, Lesniewska E, Gasquet B, Paul C, Moreau M, Denat F, Masson D, Lagrost L, Gautier T. Polysaccharide Chain Length of Lipopolysaccharides From Salmonella Minnesota Is a Determinant of Aggregate Stability, Plasma Residence Time and Proinflammatory Propensity in vivo. Front Microbiol 2019; 10:1774. [PMID: 31428071 PMCID: PMC6688513 DOI: 10.3389/fmicb.2019.01774] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/18/2019] [Indexed: 01/22/2023] Open
Abstract
Lipopolysaccharides (LPS) originate from the outer membrane of Gram-negative bacteria and trigger an inflammatory response via the innate immune system. LPS consist of a lipid A moiety directly responsible for the stimulation of the proinflammatory cascade and a polysaccharide chain of variable length. LPS form aggregates of variable size and structure in aqueous media, and the aggregation/disaggregation propensity of LPS is known as a key determinant of their biological activity. The aim of the present study was to determine to which extent the length of the polysaccharide chain can affect the nature of LPS structures, their pharmacokinetics, and eventually their proinflammatory properties in vivo. LPS variants of Salmonella Minnesota with identical lipid A but with different polysaccharide moieties were used. The physical properties of LPS aggregates were analyzed by zetametry, dynamic light scattering, and microscopy. The stability of LPS aggregates was tested in the presence of plasma, whole blood, and cultured cell lines. LPS pharmacokinetics was performed in wild-type mice. The accumulation in plasma of rough LPS (R-LPS) with a short polysaccharidic chain was lower, and its hepatic uptake was faster as compared to smooth LPS (S-LPS) with a long polysaccharidic chain. The inflammatory response was weaker with R-LPS than with S-LPS. As compared to S-LPS, R-LPS formed larger aggregates, with a higher hydrophobicity index, a more negative zeta potential, and a higher critical aggregation concentration. The lower stability of R-LPS aggregates could be illustrated in vitro by a higher extent of association of LPS to plasma lipoproteins, faster binding to blood cells, and increased uptake by macrophages and hepatocytes, compared to S-LPS. Our data indicate that a long polysaccharide chain is associated with the formation of more stable aggregates with extended residence time in plasma and higher inflammatory potential. These results show that polysaccharide chain length, and overall aggregability of LPS might be helpful to predict the proinflammatory effect that can be expected in experimental settings using LPS preparations. In addition, better knowledge and control of LPS aggregation and disaggregation might lead to new strategies to enhance LPS detoxification in septic patients.
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Affiliation(s)
- Wahib Sali
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Danish Patoli
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Jean-Paul Pais de Barros
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Jérôme Labbé
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Valérie Deckert
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Vincent Duhéron
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Naig Le Guern
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Denis Blache
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Denis Chaumont
- UMR6303 Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS/University of Bourgogne Franche-Comté, Dijon, France
| | - Eric Lesniewska
- UMR6303 Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS/University of Bourgogne Franche-Comté, Dijon, France
| | - Benoit Gasquet
- Cell Imaging platform, Inserm/University of Bourgogne Franche-Comté, Dijon, France
| | - Catherine Paul
- Laboratoire d'Immunologie et Immunothérapie des Cancers, EPHE, PSL Research University, Paris, France.,LIIC, EA7269, University of Bourgogne Franche-Comté, Dijon, France
| | - Mathieu Moreau
- Institut de Chimie Moléculaire de Bourgogne, UMR6302, CNRS/University of Bourgogne Franche-Comté, Dijon, France
| | - Franck Denat
- Institut de Chimie Moléculaire de Bourgogne, UMR6302, CNRS/University of Bourgogne Franche-Comté, Dijon, France
| | - David Masson
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France.,University Hospital of Dijon, Dijon, France
| | - Laurent Lagrost
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France.,University Hospital of Dijon, Dijon, France
| | - Thomas Gautier
- LipSTIC LabEx, UMR1231, Lipids Nutrition Cancer, Inserm/University of Bourgogne Franche-Comté, Dijon, France
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Garate JA, Stöckl J, Fernández-Alonso MDC, Artner D, Haegman M, Oostenbrink C, Jiménez-Barbero J, Beyaert R, Heine H, Kosma P, Zamyatina A. Anti-endotoxic activity and structural basis for human MD-2·TLR4 antagonism of tetraacylated lipid A mimetics based on βGlcN(1↔1)αGlcN scaffold. Innate Immun 2014; 21:490-503. [PMID: 25394365 PMCID: PMC4452626 DOI: 10.1177/1753425914550426] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/11/2014] [Indexed: 01/25/2023] Open
Abstract
Interfering with LPS binding by the co-receptor protein myeloid differentiation factor 2 (MD-2) represents a useful approach for down-regulation of MD-2·TLR4-mediated innate immune signaling, which is implicated in the pathogenesis of a variety of human diseases, including sepsis syndrome. The antagonistic activity of a series of novel synthetic tetraacylated bis-phosphorylated glycolipids based on the βGlcN(1↔1)αGlcN scaffold was assessed in human monocytic macrophage-like cell line THP-1, dendritic cells and human epithelial cells. Two compounds were shown to inhibit efficiently the LPS-induced inflammatory signaling by down-regulation of the expression of TNF-α, IL-6, IL-8, IL-10 and IL-12 to background levels. The binding of the tetraacylated by (R)-3-hydroxy-fatty acids (2 × C12, 2 × C14), 4,4′-bisphosphorylated βGlcN(1↔1)αGlcN-based lipid A mimetic DA193 to human MD-2 was calculated to be 20-fold stronger than that of Escherichia coli lipid A. Potent antagonistic activity was related to a specific molecular shape induced by the β,α(1↔1)-diglucosamine backbone. ‘Co-planar’ relative arrangement of the GlcN rings was inflicted by the double exo-anomeric conformation around both glycosidic torsions in the rigid β,α(1↔1) linkage, which was ascertained using NOESY NMR experiments and confirmed by molecular dynamics simulation. In contrast to the native lipid A ligands, the binding affinity of βGlcN(1↔1)αGlcN-based lipid A mimetics to human MD-2 was independent on the orientation of the diglucosamine backbone of the synthetic antagonist within the binding pocket of hMD-2 (rotation by 180°) allowing for two equally efficient binding modes as shown by molecular dynamics simulation.
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Affiliation(s)
- Jose Antonio Garate
- Institute of Molecular Modelling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Johannes Stöckl
- Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | | | - Daniel Artner
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Mira Haegman
- Department for Biomedical Molecular Biology, Unit of Molecular Signal Transduction in Inflammation, Ghent University, Inflammation Research Center, VIB, Ghent, Belgium
| | - Chris Oostenbrink
- Institute of Molecular Modelling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Rudi Beyaert
- Department for Biomedical Molecular Biology, Unit of Molecular Signal Transduction in Inflammation, Ghent University, Inflammation Research Center, VIB, Ghent, Belgium
| | - Holger Heine
- Research Group Innate Immunity, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), Borstel, Germany
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
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8
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Hurley JC. Towards clinical applications of anti-endotoxin antibodies; a re-appraisal of the disconnect. Toxins (Basel) 2013; 5:2589-620. [PMID: 24351718 PMCID: PMC3873702 DOI: 10.3390/toxins5122589] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/09/2013] [Accepted: 12/13/2013] [Indexed: 12/21/2022] Open
Abstract
Endotoxin is a potent mediator of a broad range of patho-physiological effects in humans. It is present in all Gram negative (GN) bacteria. It would be expected that anti-endotoxin therapies, whether antibody based or not, would have an important adjuvant therapeutic role along with antibiotics and other supportive therapies for GN infections. Indeed there is an extensive literature relating to both pre-clinical and clinical studies of anti-endotoxin antibodies. However, the extent of disconnect between the generally successful pre-clinical studies versus the failures of the numerous large clinical trials of antibody based and other anti-endotoxin therapies is under-appreciated and unexplained. Seeking a reconciliation of this disconnect is not an abstract academic question as clinical trials of interventions to reduce levels of endotoxemia levels are ongoing. The aim of this review is to examine new insights into the complex relationship between endotoxemia and sepsis in an attempt to bridge this disconnect. Several new factors to consider in this reappraisal include the frequency and types of GN bacteremia and the underlying mortality risk in the various study populations. For a range of reasons, endotoxemia can no longer be considered as a single entity. There are old clinical trials which warrant a re-appraisal in light of these recent advances in the understanding of the structure-function relationship of endotoxin. Fundamentally however, the disconnect not only remains, it has enlarged.
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Affiliation(s)
- James C Hurley
- Rural Health Academic Center, Melbourne Medical School, University of Melbourne, Parkville 3010, Australia.
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9
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Pulido D, Nogués MV, Boix E, Torrent M. Lipopolysaccharide neutralization by antimicrobial peptides: a gambit in the innate host defense strategy. J Innate Immun 2012; 4:327-36. [PMID: 22441679 DOI: 10.1159/000336713] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 01/20/2012] [Indexed: 01/08/2023] Open
Abstract
Antimicrobial peptides (AMPs) are nowadays understood as broad multifunctional tools of the innate immune system to fight microbial infections. In addition to its direct antimicrobial action, AMPs can modulate the host immune response by promoting or restraining the recruitment of cells and chemicals to the infection focus. Binding of AMPs to lipopolysaccharide is a critical step for both their antimicrobial action and their immunomodulatory properties. On the one hand, removal of Gram-negative bacteria by AMPs can be an effective strategy to prevent a worsened inflammatory response that may lead to septic shock. On the other hand, by neutralizing circulating endotoxins, AMPs can successfully reduce nitric oxide and tumor necrosis factor-α production, hence preventing severe tissue damage. Furthermore, AMPs can also interfere with the Toll-like receptor 4 recognition system, suppressing cytokine production and contributing to modulate the inflammatory response. Here, we review the immune system strategies devised by AMPs to avoid an exacerbated inflammatory response and thus prevent a fatal end to the host.
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Affiliation(s)
- David Pulido
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
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10
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Synthetic molecules and functionalized nanoparticles targeting the LPS-TLR4 signaling: A new generation of immunotherapeutics. PURE APPL CHEM 2011. [DOI: 10.1351/pac-con-11-10-35] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Toll-like receptor 4 (TLR4), the receptor of bacterial endotoxins in mammalians, plays a pivotal role in the induction of innate immunity and inflammation. TLR4 activation by bacterial lipopolysaccharide (LPS) is achieved by the coordinate and sequential action of three other proteins, the lipopolysaccharide binding protein (LBP), the cluster differentiation antigen CD14, and the myeloid differentiation protein (MD-2) receptors, that bind LPS and present it in a monomeric form to TLR4 by forming the activated [TLR4·MD-2·LPS]2 complex. Small molecules and nanoparticles active in modulating the TLR4 signal by targeting directly the MD-2·TLR4 complex or by interfering in other points of the TLR4 signaling are presented in this paper. These compounds have great pharmacological interest as vaccine adjuvants, immunotherapeutics, anti-sepsis, and anti-inflammatory agents.
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11
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Piazza M, Yu L, Teghanemt A, Gioannini T, Weiss J, Peri F. Evidence of a specific interaction between new synthetic antisepsis agents and CD14. Biochemistry 2010; 48:12337-44. [PMID: 19928913 DOI: 10.1021/bi901601b] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Synthetic molecules derived from natural sugars with a positively charged amino group or ammonium salt and two lipophilic chains have been shown to inhibit TLR4 activation in vitro and in vivo. To characterize the mechanism of action of this class of molecules, we investigated possible interactions with the extracellular components that bind and shuttle endotoxin [lipopolysaccharide (LPS)] to TLR4, namely, LBP, CD14, and MD-2. Molecules that inhibited TLR4 activation inhibited LBP.CD14-dependent transfer of endotoxin monomers derived from aggregates of tritiated lipooligosaccharide ([(3)H]LOS) from Neisseria meninigitidis to MD-2.TLR4, resulting in a reduced level of formation of a ([(3)H]LOS.MD-2.TLR4(ECD))(2) (M(r) approximately 190000) complex. This effect was due to inhibition of the transfer of [(3)H]LOS from aggregates in solution to sCD14 with little or no effect on [(3)H]LOS shuttling from [(3)H]LOS.sCD14 to MD-2. These compounds also inhibited transfer of the [(3)H]LOS monomer from full-length CD14 to a truncated, polyhistidine-tagged CD14. Dose-dependent inhibition of the transfer of [(3)H]LOS between the two forms of CD14 was observed with each of three different synthetic compounds that inhibited TLR4 activation but not by another structurally related analogue that lacked TLR4 antagonistic activity. Saturation transfer difference (STD) NMR data showed direct binding to CD14 by the synthetic TLR4 antagonist mediated principally through the lipid chains of the synthetic compound. Taken together, our findings strongly suggest that these compounds inhibit TLR4 activation by endotoxin by competitively occupying CD14 and thereby reducing the level of delivery of activating endotoxin to MD-2.TLR4.
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Affiliation(s)
- Matteo Piazza
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
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12
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Andrä J, Howe J, Garidel P, Rössle M, Richter W, Leiva-León J, Moriyon I, Bartels R, Gutsmann T, Brandenburg K. Mechanism of interaction of optimized Limulus-derived cyclic peptides with endotoxins: thermodynamic, biophysical and microbiological analysis. Biochem J 2007; 406:297-307. [PMID: 17501719 PMCID: PMC1948972 DOI: 10.1042/bj20070279] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
On the basis of formerly investigated peptides corresponding to the endotoxin-binding domain from LALF [Limulus anti-LPS (lipopolysaccharide) factor], a protein from Limulus polyphemus, we have designed and synthesized peptides of different lengths with the aim of obtaining potential therapeutic agents against septic shock syndrome. For an understanding of the mechanisms of action, we performed a detailed physicochemical and biophysical analysis of the interaction of rough mutant LPS with these peptides by applying FTIR (Fourier-transform infrared) spectroscopy, SAXS (small-angle X-ray scattering), calorimetric techniques [DSC (differential scanning calorimetry) and ITC (isothermal titration calorimetry)] and FFTEM (freeze-fracture transmission electron microscopy). Also, the action of the peptides on bacteria of different origin in microbial assays was investigated. Using FTIR and DSC, our results indicated a strong fluidization of the lipid A acyl chains due to peptide binding, with a decrease in the endothermic melting enthalpy change of the acyl chains down to a complete disappearance in the 1:0.5 to 1:2 [LPS]:[peptide] molar ratio range. Via ITC, it was deduced that the binding is a clearly exothermic process which becomes saturated at a 1:0.5 to 1:2 [LPS]:[peptide] molar ratio range. The results obtained with SAXS indicated a drastic change of the aggregate structures of LPS into a multilamellar stack, which was visualized in electron micrographs as hundreds of lamellar layers. This can be directly correlated with the inhibition of the LPS-induced production of tumour necrosis factor alpha in human mononuclear cells, but not with the action of the peptides on bacteria.
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Affiliation(s)
- Jörg Andrä
- *Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Biophysik, Parkallee 10, 23845 Borstel, Germany
| | - Jörg Howe
- *Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Biophysik, Parkallee 10, 23845 Borstel, Germany
| | - Patrick Garidel
- †Institut für Physikalische Chemie, Martin-Luther-Universität Halle-Wittenberg, Mühlpforte 1, 06108 Halle, Germany
| | - Manfred Rössle
- ‡European Molecular Biology Laboratory c/o DESY, Notkestr. 85, 22603 Hamburg, Germany
| | - Walter Richter
- §Friedrich-Schiller-Universität Jena, Elektronenmikroskopisches Zentrum der Medizinischen Fakultät, Ziegelmühlenweg 1, 07740 Jena, Germany
| | - José Leiva-León
- ∥Departamento de Microbiologia, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain
| | - Ignacio Moriyon
- ∥Departamento de Microbiologia, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain
| | - Rainer Bartels
- *Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Biophysik, Parkallee 10, 23845 Borstel, Germany
| | - Thomas Gutsmann
- *Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Biophysik, Parkallee 10, 23845 Borstel, Germany
| | - Klaus Brandenburg
- *Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Biophysik, Parkallee 10, 23845 Borstel, Germany
- To whom correspondence should be addressed (email )
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