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Brugger D, Wilhelm B, Schusser B, Gisch N, Matthes J, Zhao J, Windisch W. Masson Pine pollen (Pinus massoniana) activate HD11 chicken macrophages invitro. JOURNAL OF ETHNOPHARMACOLOGY 2024; 325:117870. [PMID: 38331121 DOI: 10.1016/j.jep.2024.117870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/10/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Masson Pine pollen (Pinus massoniana; MP) are used in Traditional Chinese Medicine to treat gut conditions. Early in vivo work supports this claim and suggests interaction of the material with the gastrointestinal immune system. AIM OF THE STUDY The present study tested if and how MP material activates HD11 chicken macrophages in vitro using material from different production sites and harvest years. MATERIAL & METHODS We applied twelve batches of MP from different Chinese production sites and harvest years. Materials were subjected to LAL tests (endotoxic activity), GC-MS (fatty acid analysis), and plate techniques (microbiological background, antimicrobial activity). Furthermore, HD11 chicken macrophages were challenged (6 h, 37 °C) with MP or LPS (E. coli O111:B4), respectively, to quantify nitric oxide (NO) production and immune gene expression (RT-qPCR). RESULTS MP material promoted strong signals in LAL tests and contained significant amounts of 3-hydroxydodecanoic acid and 3-hydroxymyristic acid, irrespective of processing, harvest year, or origin. The pollen material activated HD11 chicken macrophages, which was confirmed by spikes of NO release and k-means cluster analysis of TLR-signaling pathway gene expression data. Response of NO production to Log2-titration of MP and LPS-treated media was in any case linear and significant. The response was reduced by polymyxin-B (PMB) and the inhibition was twice as strong for LPS than MP. No or minor microbiological background was detected on the majority of MP samples. Three samples showed presence of spoilage microorganisms and Gram-negative bacteria, but this did not correlate to LAL data or bacterial DNA counts. No antimicrobial activity of MP was evident. CONCLUSION Pollen of the Masson Pine activated HD11 chicken macrophages in vitro, which is likely partially due to a background of bacterial LPS associated with the pollen material. However, as most of the effect (appr. 80%) could not be blocked by PMB this is certainly due to other stimuli. We hypothesize that polysaccharides and oligosaccharides of the pollen matrix have the potential to interact with certain immune receptors presented on the plasma membrane of chicken macrophages.
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Affiliation(s)
- Daniel Brugger
- Institute of Animal Nutrition and Dietetics, Vetsuisse-Faculty, University of Zurich, Winterthurerstrasse 270, 8057, Zurich, Switzerland; Chair of Animal Nutrition, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Strasse 2, 85354, Freising, Germany.
| | - Belinda Wilhelm
- Chair of Animal Nutrition, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Strasse 2, 85354, Freising, Germany.
| | - Benjamin Schusser
- Reproductive Biotechnology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Strasse 1, 85354, Freising, Germany; Center for Infection Prevention (ZIP), Technical University of Munich, Germany.
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, 23845, Borstel, Germany.
| | - Julia Matthes
- Chair of Animal Hygiene, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Germany; Faculty of Life Sciences, Albstadt-Sigmaringen University, Anton-Guenther-Strasse 51, 72488, Sigmaringen, Germany.
| | - Jie Zhao
- Chair of Animal Nutrition, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Strasse 2, 85354, Freising, Germany.
| | - Wilhelm Windisch
- Chair of Animal Nutrition, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Strasse 2, 85354, Freising, Germany.
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Slingerland C, Martin NI. Recent Advances in the Development of Polymyxin Antibiotics: 2010-2023. ACS Infect Dis 2024; 10:1056-1079. [PMID: 38470446 PMCID: PMC11019560 DOI: 10.1021/acsinfecdis.3c00630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 03/13/2024]
Abstract
The polymyxins are nonribosomal lipopeptides produced by Paenibacillus polymyxa and are potent antibiotics with activity specifically directed against Gram-negative bacteria. While the clinical use of polymyxins has historically been limited due to their toxicity, their use is on the rise given the lack of alternative treatment options for infections due to multidrug resistant Gram-negative pathogens. The Gram-negative specificity of the polymyxins is due to their ability to target lipid A, the membrane embedded LPS anchor that decorates the cell surface of Gram-negative bacteria. Notably, the mechanisms responsible for polymyxin toxicity, and in particular their nephrotoxicity, are only partially understood with most insights coming from studies carried out in the past decade. In parallel, many synthetic and semisynthetic polymyxin analogues have been developed in recent years in an attempt to mitigate the nephrotoxicity of the natural products. Despite these efforts, to date, no polymyxin analogues have gained clinical approval. This may soon change, however, as at the moment there are three novel polymyxin analogues in clinical trials. In this context, this review provides an update of the most recent insights with regard to the structure-activity relationships and nephrotoxicity of new polymyxin variants reported since 2010. We also discuss advances in the synthetic methods used to generate new polymyxin analogues, both via total synthesis and semisynthesis.
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Affiliation(s)
- Cornelis
J. Slingerland
- Biological
Chemistry Group, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Nathaniel I. Martin
- Biological
Chemistry Group, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
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3
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Lim AL, Miller BW, Lin Z, Fisher MA, Barrows LR, Haygood MG, Schmidt EW. Resistance mechanisms for Gram-negative bacteria-specific lipopeptides, turnercyclamycins, differ from that of colistin. Microbiol Spectr 2023; 11:e0230623. [PMID: 37882570 PMCID: PMC10714751 DOI: 10.1128/spectrum.02306-23] [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: 06/05/2023] [Accepted: 09/13/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Bacterial resistance to antibiotics is a crisis. Acinetobacter baumannii is among the CDC urgent threat pathogens in part for this reason. Lipopeptides known as turnercyclamycins are produced by symbiotic bacteria that normally live in marine mollusks, where they may be involved in shaping their symbiotic niche. Turnercyclamycins killed Gram-negative pathogens including drug-resistant Acinetobacter, but how do the mechanisms of resistance compare to other lipopeptide drugs? Here, we define resistance from a truncation of MlaA, a protein involved in regulating bacterial membrane phospholipids. Intriguingly, this resistance mechanism only affected one turnercyclamycin variant, which differed only in two atoms in the lipid tail of the compounds. We could not obtain significant resistance to the second turnercyclamycin variant, which was also effective in an infection model. This study reveals an unexpected subtlety in resistance to lipopeptide antibiotics, which may be useful in the design and development of antibiotics to combat drug resistance.
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Affiliation(s)
- Albebson L. Lim
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Bailey W. Miller
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Zhenjian Lin
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Mark A. Fisher
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, Utah, USA
| | - Louis R. Barrows
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Margo G. Haygood
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Eric W. Schmidt
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
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4
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Slingerland CJ, Lysenko V, Chaudhuri S, Wesseling CMJ, Barnes D, Masereeuw R, Martin NI. Semisynthetic polymyxins with potent antibacterial activity and reduced kidney cell toxicity. RSC Med Chem 2023; 14:2417-2425. [PMID: 37974968 PMCID: PMC10650952 DOI: 10.1039/d3md00456b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/06/2023] [Indexed: 11/19/2023] Open
Abstract
The growing incidence of infections caused by multi-drug resistant Gram-negative bacteria has led to an increased use of last-resort antibiotics such as the polymyxins. Polymyxin therapy is limited by toxicity concerns, most notably nephrotoxicity. Recently we reported the development of a novel class of semisynthetic polymyxins with reduced toxicity wherein the N-terminal lipid and diaminobutyric acid residue are replaced by a cysteine-linked lipid featuring a reductively labile disulfide bond. In the present study we further explored the potential of this approach by also varying the amino acid residue directly adjacent to the polymyxin macrocycle. This led to the identification of new semisynthetic polymyxins that maintain the potent antibacterial activity of the clinically used polymyxin B while exhibiting a further reduction in toxicity toward human proximal tubule epithelial cells. Furthermore, these new polymyxins were found to effectively synergize with novobiocin, rifampicin, and erythromycin against mcr-positive, polymyxin resistant E. coli.
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Affiliation(s)
- Cornelis J Slingerland
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University Sylviusweg 72 2333 BE Leiden The Netherlands
| | - Vladyslav Lysenko
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University Sylviusweg 72 2333 BE Leiden The Netherlands
| | - Samhita Chaudhuri
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University Sylviusweg 72 2333 BE Leiden The Netherlands
| | - Charlotte M J Wesseling
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University Sylviusweg 72 2333 BE Leiden The Netherlands
| | - Devon Barnes
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Utrecht University 3584 CG Utrecht The Netherlands
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Utrecht University 3584 CG Utrecht The Netherlands
| | - Nathaniel I Martin
- Biological Chemistry Group, Institute of Biology Leiden, Leiden University Sylviusweg 72 2333 BE Leiden The Netherlands
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5
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Slingerland C, Kotsogianni I, Wesseling CMJ, Martin NI. Polymyxin Stereochemistry and Its Role in Antibacterial Activity and Outer Membrane Disruption. ACS Infect Dis 2022; 8:2396-2404. [PMID: 36342383 PMCID: PMC9745799 DOI: 10.1021/acsinfecdis.2c00307] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
With increasing rates of resistance toward commonly used antibiotics, especially among Gram-negative bacteria, there is renewed interested in polymyxins. Polymyxins are lipopeptide antibiotics with potent anti-Gram-negative activity and are generally believed to target lipid A, the lipopolysaccharide (LPS) anchor found in the outer membrane of Gram-negative bacteria. To characterize the stereochemical aspects of their mechanism(s) of action, we synthesized the full enantiomers of polymyxin B and the polymyxin B nonapeptide (PMBN). Both compounds were compared with the natural compounds in biological and biophysical assays, revealing strongly reduced antibacterial activity for the enantiomeric species. The enantiomeric compounds also exhibit reduced LPS binding, lower outer membrane (OM) permeabilization, and loss of synergetic potential. These findings provide new insights into the stereochemical requirements underlying the mechanisms of action of polymyxin B and PMBN.
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6
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Synergistic Membrane Disturbance Improves the Antibacterial Performance of Polymyxin B. Polymers (Basel) 2022; 14:polym14204316. [PMID: 36297894 PMCID: PMC9611124 DOI: 10.3390/polym14204316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/29/2022] [Accepted: 10/09/2022] [Indexed: 01/24/2023] Open
Abstract
Drug-resistant Gram-negative bacteria pose a serious threat to public health, and polymyxin B (PMB) is clinically used as a last-line therapy for the treatment of infections caused by these pathogens. However, the appearance of PMB resistance calls for an effort to develop new approaches to improve its antibacterial performance. In this work, a new type of nanocomposite, composed of PMB molecules being chemically decorated on the surface of graphene oxide (GO) nanosheets, was designed, which showed potent antibacterial ability through synergistically and physically disturbing the bacterial membrane. The as-fabricated PMB@GO nanocomposites demonstrated an enhanced bacterial-killing efficiency, with a minimum inhibitory concentration (MIC) value half of that of free PMB (with an MIC value as low as 0.5 μg mL-1 over Escherichia coli), and a bacterial viability less than one fourth of that of PMB (with a bacterial reduction of 60% after 3 h treatment, and 90% after 6 h incubation). Furthermore, the nanocomposite displayed moderate cytotoxicity or hemolysis effect, with cellular viabilities over 85% at concentrations up to 16 times the MIC value. Studies on antibacterial mechanism revealed that the synergy between PMB molecules and GO nanosheets greatly facilitated the vertical insertion of the nanocomposite into the lipid membrane, leading to membrane disturbance and permeabilization. Our results demonstrate a physical mechanism for improving the antibacterial performance of PMB and developing advanced antibacterial agents for better clinic uses.
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7
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Li W, Yu B. Temporary ether protecting groups at the anomeric center in complex carbohydrate synthesis. Adv Carbohydr Chem Biochem 2020; 77:1-69. [PMID: 33004110 DOI: 10.1016/bs.accb.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis of a carbohydrate building block usually starts with introduction of a temporary protecting group at the anomeric center and ends with its selective cleavage for further transformation. Thus, the choice of the anomeric temporary protecting group must be carefully considered because it should retain intact during the whole synthetic manipulation, and it should be chemoselectively removable without affecting other functional groups at a late stage in the synthesis. Etherate groups are the most widely used temporary protecting groups at the anomeric center, generally including allyl ethers, MP (p-methoxyphenyl) ethers, benzyl ethers, PMB (p-methoxybenzyl) eithers, and silyl ethers. This chapter provides a comprehensive review on their formation, cleavage, and applications in the synthesis of complex carbohydrates.
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Affiliation(s)
- Wei Li
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, China.
| | - Biao Yu
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.
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8
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Liu K, Wang L, Guo Z. An extensive review of studies on mycobacterium cell wall polysaccharide-related oligosaccharides – part III: synthetic studies and biological applications of arabinofuranosyl oligosaccharides and their analogs, derivatives and conjugates. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1630841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kechun Liu
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji′nan, Shandong, China
| | - Lizhen Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji′nan, Shandong, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL, USA
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9
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Itoh H, Inoue M. Comprehensive Structure–Activity Relationship Studies of Macrocyclic Natural Products Enabled by Their Total Syntheses. Chem Rev 2019; 119:10002-10031. [DOI: 10.1021/acs.chemrev.9b00063] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Hiroaki Itoh
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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10
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Study of the structure-activity relationship of polymyxin analogues. Bioorg Med Chem Lett 2018; 28:2713-2716. [DOI: 10.1016/j.bmcl.2018.03.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/06/2018] [Accepted: 03/11/2018] [Indexed: 12/30/2022]
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11
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Gao J, Guo Z. Progress in the synthesis and biological evaluation of lipid A and its derivatives. Med Res Rev 2018; 38:556-601. [PMID: 28621828 PMCID: PMC5732894 DOI: 10.1002/med.21447] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 03/09/2017] [Accepted: 04/20/2017] [Indexed: 12/31/2022]
Abstract
Lipid A is one of the core structures of bacterial lipopolysaccharides (LPSs), and it is mainly responsible for the strong immunostimulatory activities of LPS through interactions with the Toll-like receptors and other molecules in the human immune system. To obtain structurally homogeneous and well-defined lipid As and its derivatives in quantities meaningful for various biological studies and applications, their chemical synthesis has become a focal point. This review has provided a survey of significant progresses made in the synthesis of lipid A, and its derivatives that carry diverse saturated and unsaturated lipids, have the phosphate group at its reducing end replaced with a more stable phosphate or carboxyl group, or lack the reducing end phosphate or both phosphate groups, as well as progresses in the synthesis of LPS analogs and other lipid A conjugates. These synthetic molecules have facilitated the elucidation of the structure-activity relationships of lipid A useful for the design and development of lipid A based therapeutics, such as those utilized to treat sepsis, and other medical applications, for example the use of monophosphoryl lipid A as a carrier molecule for the study of fully synthetic self-adjuvanting conjugate vaccines. These topics are also briefly covered in the current review.
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Affiliation(s)
- Jian Gao
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, 214 Leigh Hall, Gainesville, Florida 32611, United States
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12
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Wang L, Feng S, Wang S, Li H, Guo Z, Gu G. Synthesis and Immunological Comparison of Differently Linked Lipoarabinomannan Oligosaccharide–Monophosphoryl Lipid A Conjugates as Antituberculosis Vaccines. J Org Chem 2017; 82:12085-12096. [DOI: 10.1021/acs.joc.7b01817] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Lizhen Wang
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Shaojie Feng
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Subo Wang
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Hui Li
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Zhongwu Guo
- Department
of Chemistry, University of Florida, 214 Leigh Hall, Gainesville, Florida 32611, United States
| | - Guofeng Gu
- National
Glycoengineering Research Center and Shandong Provincial Key Laboratory
of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
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13
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Branched Peptide, B2088, Disrupts the Supramolecular Organization of Lipopolysaccharides and Sensitizes the Gram-negative Bacteria. Sci Rep 2016; 6:25905. [PMID: 27174567 PMCID: PMC4865820 DOI: 10.1038/srep25905] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/25/2016] [Indexed: 12/30/2022] Open
Abstract
Dissecting the complexities of branched peptide-lipopolysaccharides (LPS) interactions provide rationale for the development of non-cytotoxic antibiotic adjuvants. Using various biophysical methods, we show that the branched peptide, B2088, binds to lipid A and disrupts the supramolecular organization of LPS. The disruption of outer membrane in an intact bacterium was demonstrated by fluorescence spectroscopy and checkerboard assays, the latter confirming strong to moderate synergism between B2088 and various classes of antibiotics. The potency of synergistic combinations of B2088 and antibiotics was further established by time-kill kinetics, mammalian cell culture infections model and in vivo model of bacterial keratitis. Importantly, B2088 did not show any cytotoxicity to corneal epithelial cells for at least 96 h continuous exposure or hemolytic activity even at 20 mg/ml. Peptide congeners containing norvaline, phenylalanine and tyrosine (instead of valine in B2088) displayed better synergism compared to other substitutions. We propose that high affinity and subsequent disruption of the supramolecular assembly of LPS by the branched peptides are vital for the development of non-cytotoxic antibiotic adjuvants that can enhance the accessibility of conventional antibiotics to the intracellular targets, decrease the antibiotic consumption and holds promise in averting antibiotic resistance.
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't Hart P, Oppedijk SF, Breukink E, Martin NI. New Insights into Nisin's Antibacterial Mechanism Revealed by Binding Studies with Synthetic Lipid II Analogues. Biochemistry 2015; 55:232-7. [PMID: 26653142 DOI: 10.1021/acs.biochem.5b01173] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nisin is the preeminent lantibiotic, and to date its antibacterial mechanism has been investigated using a variety of techniques. While nisin's lipid II-mediated mode of action is well-established, a detailed analysis of the thermodynamic parameters governing this interaction has not been previously reported. We here describe an approach employing isothermal titration calorimetry to directly measure the affinity of nisin for lipid II and a number of synthetic lipid II precursors and analogues. Our measurements confirm the pyrophosphate unit of lipid II as the primary site of nisin binding and also indicate that the complete MurNAc moiety is required for a high-affinity interaction. Additionally, we find that while the pentapeptide unit of the lipid II molecule is not required for strong binding by nisin, it does play an important role in stabilizing the subsequently formed nisin-lipid II pore complex, albeit at an entropic cost. The anchoring of lipid II in a membrane environment was also found to play a significant role in enhancing nisin binding and is required in order to achieve a high-affinity interaction.
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Affiliation(s)
- Peter 't Hart
- Department of Medicinal Chemistry & Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Sabine F Oppedijk
- Membrane Biochemistry and Biophysics Group, Department of Chemistry, Utrecht University , Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Eefjan Breukink
- Membrane Biochemistry and Biophysics Group, Department of Chemistry, Utrecht University , Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Nathaniel I Martin
- Department of Medicinal Chemistry & Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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15
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Murzyn K, Pasenkiewicz-Gierula M. Structural Properties of the Water/Membrane Interface of a Bilayer Built of the E. coli Lipid A. J Phys Chem B 2015; 119:5846-56. [DOI: 10.1021/jp5119629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Krzysztof Murzyn
- Department
of Computational
Biophysics and Bioinformatics, Faculty of Biochemistry,
Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Marta Pasenkiewicz-Gierula
- Department
of Computational
Biophysics and Bioinformatics, Faculty of Biochemistry,
Biophysics, and Biotechnology, Jagiellonian University, Kraków, Poland
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16
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Wong PT, Tang S, Tang K, Coulter A, Mukherjee J, Gam K, Baker JR, Choi SK. A lipopolysaccharide binding heteromultivalent dendrimer nanoplatform for Gram negative cell targeting. J Mater Chem B 2015; 3:1149-1156. [DOI: 10.1039/c4tb01690d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Heteromultivalent design of PAMAM dendrimer by conjugation with polymyxin B (PMB) ligand and excess auxiliary ethanolamine (EA) branches led to lipopolysaccharide (LPS) avidity two orders of magnitude greater than free PMB.
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Affiliation(s)
- Pamela T. Wong
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
- Department of Internal Medicine
| | - Shengzhuang Tang
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
- Department of Internal Medicine
| | - Kenny Tang
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Alexa Coulter
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Jhindan Mukherjee
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
- Department of Internal Medicine
| | - Kristina Gam
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - James R. Baker
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
- Department of Internal Medicine
| | - Seok Ki Choi
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
- Department of Internal Medicine
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17
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Tang S, Wang Q, Guo Z. Synthesis of a monophosphoryl derivative of Escherichia coli lipid A and its efficient coupling to a tumor-associated carbohydrate antigen. Chemistry 2010; 16:1319-25. [PMID: 19943286 PMCID: PMC2867242 DOI: 10.1002/chem.200902153] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Monophosphoryl lipid A is a safe and potent immunostimulant and vaccine adjuvant, which is potentially useful for the development of effective carbohydrate-based conjugate vaccines. This paper presents a convergent and efficient synthesis of a monophosphoryl derivative of E. coli lipid A that has an alkyne functionality at the reducing end, which is suitable for coupling with various molecules. The coupling of this derivative to an N-modified analogue of tumor-associated antigen GM3 through click chemistry is also presented.
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Affiliation(s)
- Shouchu Tang
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA, Fax: (+) 1-313-557-8822
| | - Qianli Wang
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA, Fax: (+) 1-313-557-8822
| | - Zhongwu Guo
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA, Fax: (+) 1-313-557-8822
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18
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Wang Q, Xue J, Guo Z. Synthesis of a monophosphoryl lipid A derivative and its conjugation to a modified form of a tumor-associated carbohydrate antigen GM3. Chem Commun (Camb) 2009:5536-7. [PMID: 19753348 PMCID: PMC2877631 DOI: 10.1039/b907351e] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An efficient synthesis of a derivative of monophosphoryl lipid A suitable for coupling to various structures for the construction of glycoconjugate vaccines and its conjugation with an N-modified form of the tumor-associated antigen GM3 is presented.
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Affiliation(s)
- Qianli Wang
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA
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19
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Yermak IM, Davydova VN. Interaction of bacterial lipopolysaccharides with host soluble proteins and polycations. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2008. [DOI: 10.1134/s1990747808040016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Zorko M, Jerala R. Alexidine and chlorhexidine bind to lipopolysaccharide and lipoteichoic acid and prevent cell activation by antibiotics. J Antimicrob Chemother 2008; 62:730-7. [PMID: 18635521 DOI: 10.1093/jac/dkn270] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Many antibiotics used to treat infections cause release of immunostimulatory cell wall components from bacteria. Therefore, a combination of antimicrobial and endotoxin-neutralizing activity is desired to prevent inflammation induced by destroyed bacteria. Chlorhexidine and alexidine are amphipathic bisbiguanides and could neutralize bacterial membrane components as stimulators of Toll-like receptors (TLRs). METHODS Binding of chlorhexidine and alexidine to lipopolysaccharide (LPS) and lipoteichoic acid (LTA) was determined by fluorescence displacement assay and isothermal calorimetric titration. Neutralization of the biological effect of LPS and LTA on TLR-activated cellular activation was determined by NF-kappaB reporter luciferase activation on cells transfected with specific TLRs and NO production of murine macrophages in the presence of isolated agonists and antibiotic-treated bacteria. RESULTS Alexidine and chlorhexidine bind not only to LPS but also to LTA from Gram-positive bacteria. Alexidine has a higher affinity than chlorhexidine for both compounds. Calorimetric titration shows an initial endothermic contribution indicating participation of hydrophobic interactions in LPS binding, while binding to LTA displayed initial exothermic contribution. Both compounds prevent cell activation of TLR4 and TLR2 by LPS and LTA, respectively. The addition of both compounds suppressed NO production by macrophages in the presence of bacteria treated with different types of antibiotics. CONCLUSIONS Chlorhexidine and alexidine suppress bacterial membrane-induced cell activation at concentrations two orders of magnitude lower than that used in topical applications. Combining biocides with different types of antibiotics prevented macrophage activation in the presence of bacteria and demonstrated the potential of chlorhexidine and alexidine to suppress inflammatory responses caused by activation of TLRs.
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Affiliation(s)
- Mateja Zorko
- Department of Biotechnology, National Institute of Chemistry, Hajdrihova 19, Ljubljana, Slovenia
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21
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Abstract
Lipopeptide daptomycin is one of the few recently approved antibiotics based on the novel mechanism of action. Recent advances in synthetic lipopeptides, driven by the biochemical and biophysical research, expanded their spectrum of antimicrobial activity and reduced their size to achieve economically viable production. Lipopeptides, consisting of a short peptide chain conjugated with an acyl chain, form a structurally defined conformation, which inserts into the bacterial membrane and dissipates its transmembrane potential. In addition to antimicrobial activity, synthetic lipopeptides also suppress inflammation through the neutralization of bacterial agonists of the innate immune response, synergize with conventional antibiotics and have improved proteolytic stability. Activities in animal models indicate that synthetic lipopeptides may surpass the natural lipopeptides as the perspective class of anti-infective agents.
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Affiliation(s)
- Roman Jerala
- National Institute of Chemistry, Department of Biotechnology, Hajdrihova 19, Ljubljana, Slovenia.
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22
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Harper M, Cox A, St Michael F, Parnas H, Wilkie I, Blackall PJ, Adler B, Boyce JD. Decoration of Pasteurella multocida lipopolysaccharide with phosphocholine is important for virulence. J Bacteriol 2007; 189:7384-91. [PMID: 17704225 PMCID: PMC2168462 DOI: 10.1128/jb.00948-07] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphocholine (PCho) is an important substituent of surface structures expressed by a number of bacterial pathogens. Its role in virulence has been investigated in several species, in which it has been shown to play a role in bacterial adhesion to mucosal surfaces, in resistance to antimicrobial peptides, or in sensitivity to complement-mediated killing. The lipopolysaccharide (LPS) structure of Pasteurella multocida strain Pm70, whose genome sequence is known, has recently been determined and does not contain PCho. However, LPS structures from the closely related, virulent P. multocida strains VP161 and X-73 were shown to contain PCho on their terminal galactose sugar residues. To determine if PCho was involved in the virulence of P. multocida, we used subtractive hybridization of the VP161 genome against the Pm70 genome to identify a four-gene locus (designated pcgDABC) which we show is required for the addition of the PCho residues to LPS. The proteins predicted to be encoded by pcgABC showed identity to proteins involved in choline uptake, phosphorylation, and nucleotide sugar activation of PCho. We constructed a P. multocida VP161 pcgC mutant and demonstrated that this strain produces LPS that lacks PCho on the terminal galactose residues. This pcgC mutant displayed reduced in vivo growth in a chicken infection model and was more sensitive to the chicken antimicrobial peptide fowlicidin-1 than the wild-type P. multocida strain.
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Affiliation(s)
- Marina Harper
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, VIC, Australia
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23
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N-Dimethylphosphoryl-protected glucosamine trichloroacetimidate as an effective glycosylation donor. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.04.150] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Clements A, Tull D, Jenney AW, Farn JL, Kim SH, Bishop RE, McPhee JB, Hancock REW, Hartland EL, Pearse MJ, Wijburg OLC, Jackson DC, McConville MJ, Strugnell RA. Secondary acylation of Klebsiella pneumoniae lipopolysaccharide contributes to sensitivity to antibacterial peptides. J Biol Chem 2007; 282:15569-77. [PMID: 17371870 PMCID: PMC5007121 DOI: 10.1074/jbc.m701454200] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Klebsiella pneumoniae is an important cause of nosocomial Gram-negative sepsis. Lipopolysaccharide (LPS) is considered to be a major virulence determinant of this encapsulated bacterium and most mutations to the lipid A anchor of LPS are conditionally lethal to the bacterium. We studied the role of LPS acylation in K. pneumoniae disease pathogenesis by using a mutation of lpxM (msbB/waaN), which encodes the enzyme responsible for late secondary acylation of immature lipid A molecules. A K. pneumoniae B5055 (K2:O1) lpxM mutant was found to be attenuated for growth in the lungs in a mouse pneumonia model leading to reduced lethality of the bacterium. B5055DeltalpxM exhibited similar sensitivity to phagocytosis or complement-mediated lysis than B5055, unlike the non-encapsulated mutant B5055nm. In vitro, B5055DeltalpxM showed increased permeability of the outer membrane and an increased susceptibility to certain antibacterial peptides suggesting that in vivo attenuation may be due in part to sensitivity to antibacterial peptides present in the lungs of BALB/c mice. These data support the view that lipopolysaccharide acylation plays a important role in providing Gram-negative bacteria some resistance to structural and innate defenses and especially the antibacterial properties of detergents (e.g. bile) and cationic defensins.
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Affiliation(s)
- Abigail Clements
- CRC for Vaccine Technology in the Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
- Australian Bacterial Pathogenesis Program in the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Dedreia Tull
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Adam W. Jenney
- CRC for Vaccine Technology in the Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
- Australian Bacterial Pathogenesis Program in the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jacinta L. Farn
- CRC for Vaccine Technology in the Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
- Australian Bacterial Pathogenesis Program in the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sang-Hyun Kim
- Department of Biochemistry, University of Toronto, Ontario M5S1A8, Canada
| | - Russell E. Bishop
- Department of Biochemistry, University of Toronto, Ontario M5S1A8, Canada
| | - Joseph B. McPhee
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Robert E. W. Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Elizabeth L. Hartland
- CRC for Vaccine Technology in the Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
- Australian Bacterial Pathogenesis Program in the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | | | - Odilia L. C. Wijburg
- CRC for Vaccine Technology in the Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
- Australian Bacterial Pathogenesis Program in the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - David C. Jackson
- CRC for Vaccine Technology in the Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Richard A. Strugnell
- CRC for Vaccine Technology in the Department of Microbiology & Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
- Australian Bacterial Pathogenesis Program in the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
- To whom correspondence should be addressed: Dept. of Microbiology & Immunology, University of Melbourne, Parkville VIC 3010, Australia. Tel.: 61-3-8344-5712; Fax: 61-3-9347-1540;
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25
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Vesentini S, Soncini M, Zaupa A, Silvestri V, Fiore GB, Redaelli A. Multi-scale analysis of the toraymyxin adsorption cartridge. Part I: molecular interaction of polymyxin B with endotoxins. Int J Artif Organs 2006; 29:239-50. [PMID: 16552671 DOI: 10.1177/039139880602900210] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endotoxins or lipopolysaccharides are the main constituents of the outer leaflet of Gram-negative bacteria membrane and play a central role in the pathogenesis of the septic shock. Polymyxin B has both antibacterial and antiendotoxin capability; indeed it is able to destroy the bacterial outer membrane and bind endotoxin neutralizing its toxic effects. Cartridges containing polymyxin B-immobilized fibers (Toraymyxin PMX-F, Toray Industries, Japan) are used in extracorporeal hemoperfusion to remove circulating endotoxin. The aim of this study is the characterization of the polymyxin B-endotoxin system at the molecular level, thus providing quantitative evaluation of the binding forces exerted in the molecular complex. Polymyxin B was interfaced with five molecular models of lipopolysaccharides differing in their structure and molecular mechanics simulations were performed at different intermolecular distances aimed at calculating the interaction energies of the complex. Binding forces were calculated by fitting interaction energies data. Results show that in the short range the polymyxin B-endotoxin complex is mediated by hydrophobic forces and in the long range the complex is driven by ionic forces only. From a mechanical standpoint, polymyxin B-endotoxin complex is characterized by maximum binding forces ranging between 1.39 nN to 3.79 nN. The knowledge of the binding force behavior at different intermolecular distances allows further investigations at higher scale level (Part II).
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Affiliation(s)
- S Vesentini
- Department of Bioengineering, Politecnico di Milano, Milan, Italy
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26
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Nishino K, Hsu FF, Turk J, Cromie MJ, Wösten MMSM, Groisman EA. Identification of the lipopolysaccharide modifications controlled by the Salmonella PmrA/PmrB system mediating resistance to Fe(III) and Al(III). Mol Microbiol 2006; 61:645-54. [PMID: 16803591 PMCID: PMC1618816 DOI: 10.1111/j.1365-2958.2006.05273.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Iron is an essential metal but can be toxic in excess. While several homeostatic mechanisms prevent oxygen-dependent killing promoted by Fe(II), little is known about how cells cope with Fe(III), which kills by oxygen-independent means. Several Gram-negative bacterial species harbour a regulatory system – termed PmrA/PmrB – that is activated by and required for resistance to Fe(III). We now report the identification of the PmrA-regulated determinants mediating resistance to Fe(III) and Al(III) in Salmonella enterica serovar Typhimurium. We establish that these determinants remodel two regions of the lipopolysaccharide, decreasing the negative charge of this major constituent of the outer membrane. Remodelling entails the covalent modification of the two phosphates in the lipid A region with phosphoethanolamine and 4-aminoarabinose, which has been previously implicated in resistance to polymyxin B, as well as dephosphorylation of the Hep(II) phosphate in the core region by the PmrG protein. A mutant lacking the PmrA-regulated Fe(III) resistance genes bound more Fe(III) than the wild-type strain and was defective for survival in soil, suggesting that these PmrA-regulated lipopolysaccharide modifications aid Salmonella's survival and spread in non-host environments.
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Affiliation(s)
- Kunihiko Nishino
- Department of Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Department of Internal Medicine, Washington University School of Medicine660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - John Turk
- Mass Spectrometry Resource, Department of Internal Medicine, Washington University School of Medicine660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Michael J Cromie
- Department of Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Marc M S M Wösten
- Department of Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Eduardo A Groisman
- Department of Molecular Microbiology, Howard Hughes Medical Institute, Washington University School of Medicine660 South Euclid Avenue, St. Louis, MO 63110, USA
- *For correspondence. E-mail ; Tel. (+1) 314 362 3692; Fax (+1) 314 747 8228
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27
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Ni Y, Chen RR. Accelerating whole-cell biocatalysis by reducing outer membrane permeability barrier. Biotechnol Bioeng 2005; 87:804-11. [PMID: 15329939 DOI: 10.1002/bit.20202] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Whole-cell biocatalysts are preferred in many biocatalysis applications. However, due to permeability barriers imposed by cell envelopes, whole-cell catalyzed reactions are reportedly 10-100-fold slower than reactions catalyzed by free enzymes. In this study, we accelerated whole-cell biocatalysis by reducing the membrane permeability barrier using molecular engineering approaches. Escherichia coli cells with genetically altered outer membrane structures were used. Specifically, a lipopolysaccarides mutant SM101 and a Braun's lipoprotein mutant E609L were used along with two model substrates that differ substantially in size and hydrophobicity, nitrocefin, and a tetrapeptide N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide. The reduction of the outer membrane permeability by genetic methods led to significant increases (up to 380%) in reaction rates of whole-cell catalyzed reactions. The magnitude of increase in biocatalysis rates was dependent on the substrates and on the nature of mutations introduced in the outer membrane structure. Notably, mutations in outer membrane can render the outer membrane completely permeable to one substrate, a barrierless condition that maximizes the reaction rate. The impact of the mutations introduced on the permeability barrier of the membranes was compared to the impact of polymixin B nonapeptide, a known potent permeabilizer acting on lipopolysaccharides. Our results suggest that genetic modifications to enhance the permeability of hydrophilic molecules should target the Lipid A region. However, strategies other than reduction of Lipid A synthesis should be considered. As we have demonstrated with tetrapeptide, membrane engineering can be much more effective in reducing a permeability barrier than are exogenous permeabilizers. This work, to our knowledge, is the first use of a molecular membrane engineering approach to address substrate permeability limitations encountered in biocatalysis applications.
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Affiliation(s)
- Ye Ni
- Chemical Engineering Department, Virginia Commonwealth University, 601 W. Main St., Richmond 23284-3028, USA
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28
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Pollard AJ, Currie A, Rosenberger CM, Heale JP, Finlay BB, Speert DP. Differential post-transcriptional activation of human phagocytes by different Pseudomonas aeruginosa isolates. Cell Microbiol 2004; 6:639-50. [PMID: 15186400 DOI: 10.1111/j.1462-5822.2004.00388.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Pseudomonas aeruginosa is a pulmonary pathogen in individuals with impaired mucociliary clearance such as cystic fibrosis or mechanical ventilation. Non-opsonic phagocytosis of P. aeruginosa can be mediated by either CR3 or CD14 and different strains appear to have a bias towards one or the other receptor. Strain Fc808 is ingested through CD14 whereas P1 (Fc194) uses CR3. In an in vitro culture system, the inflammatory response of macrophages to these two different strains of P. aeruginosa was divergent at the protein level, with higher IL-6 and tumour necrosis factor (TNF)-alpha production generated in response to strain P1 and higher IL-1 beta production in response to strain Fc808. Interaction of macrophages with these two bacterial strains induced distinct gene expression patterns as detected by gene array analysis, with prominence of genes encoding pro-inflammatory cytokines, surface receptors, transcription factors and proteins involved in phagocytosis. However, comparison of gene expression data and cytokine response data with the two bacterial strains indicated that production of IL-1 beta, IL-6 and TNF-alpha was under differential post-transcriptional control. Interestingly, this effect did not correlate with receptor bias but instead was related to the different LPSs of the two strains. The use of specific mitogen-activated protein kinase (MAPK) inhibitors suggested a role for extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) in the differential cytokine production by strains P1 and Fc808. These results indicate that strains of the same species of bacteria may induce differential macrophage phagocytic and inflammatory responses with likely consequence for bacterial clearance and host injury.
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Affiliation(s)
- Andrew J Pollard
- Division of Infectious and Immunological Diseases, Department of Pediatrics, University of British Columbia, British Columbia's Research Institute for Children's and Women's Health, Vancouver, BC, Canada.
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29
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Abstract
Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions.
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Affiliation(s)
- Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA.
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