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Wiese A, Gutsmann T, Seydel U. Review: Towards antibacterial strategies: studies on the mechanisms of interaction between antibacterial peptides and model membranes. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519030090020101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Lipopolysaccharides (LPSs) play a dual role as inflammation-inducing and as membrane-forming molecules. The former role attracts significantly more attention from scientists, possibly because it is more closely related to sepsis and septic shock. This review aims to focus the reader's attention to the other role, the function of LPS as the major constituent of the outer layer of the outer membrane of Gram-negative bacteria, in particular those of enterobacterial strains. In this function, LPS is a necessary component of the cell envelope and guarantees survival of the bacterial organism. At the same time, it represents the first target for attacking molecules which may either be synthesized by the host's innate or adaptive immune system or administered to the human body. The interaction of these molecules with the outer membrane may not only directly cause the death of the bacterial organism, but may also lead to the release of LPS into the circulation. Here, we review membrane model systems and their application for the study of molecular mechanisms of interaction of peptides such as those of the human complement system, the bactericidal/permeability-increasing protein (BPI), cationic antibacterial peptide 18 kDa (CAP18) as an example of cathelicidins, defensins, and polymyxin B (PMB). Emphasis is on electrical measurements with a reconstitution system of the lipid matrix of the outer membrane which was established in the authors' laboratory as a planar asymmetric bilayer with one leaflet being composed solely of LPS and the other of the natural phospholipid mixture. The main conclusion, which can be drawn from these investigations, is that LPS and in general its negative charges are the dominant determinants for specific peptide—membrane interactions. However, the detailed mechanisms of interaction, which finally lead to bacterial killing, may involve further steps and differ for different antibacterial peptides.
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Affiliation(s)
- Andre Wiese
- Division of Biophysics, Research Center Borstel, Borstel, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel, Borstel, Germany
| | - Ulrich Seydel
- Division of Biophysics, Research Center Borstel, Borstel, Germany,
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Wiese A, Brandenburg K, Ulmer AJ, Seydel U, Müller-Loennies S. The dual role of lipopolysaccharide as effector and target molecule. Biol Chem 1999; 380:767-84. [PMID: 10494826 DOI: 10.1515/bc.1999.097] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lipopolysaccharides (LPS) are major integral components of the outer membrane of Gram-negative bacteria being exclusively located in its outer leaflet facing the bacterial environment. Chemically they consist in different bacterial strains of a highly variable O-specific chain, a less variable core oligosaccharide, and a lipid component, termed lipid A, with low structural variability. LPS participate in the physiological membrane functions and are, therefore, essential for bacterial growth and viability. They contribute to the low membrane permeability and increase the resistance towards hydrophobic agents. They are also the primary target for the attack of antibacterial drugs and proteins such as components of the host's immune response. When set free LPS elicit, in higher organisms, a broad spectrum of biological activities. They play an important role in the manifestation of Gram-negative infection and are therefore termed endotoxins. Physico-chemical parameters such as the molecular conformation and the charges of the lipid A portion, which is responsible for endotoxin-typical biological activities and is therefore termed the 'endotoxic principle' of LPS, are correlated with the biological activity of chemically different LPS.
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Affiliation(s)
- A Wiese
- Research Center Borstel, Center for Medicine and Biosciences, Germany
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Sauer H, Pratsch L, Tschopp J, Bhakdi S, Peters R. Functional size of complement and perforin pores compared by confocal laser scanning microscopy and fluorescence microphotolysis. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1063:137-46. [PMID: 2015253 DOI: 10.1016/0005-2736(91)90363-d] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Confocal laser scanning microscopy and fluorescence microphotolysis (also referred to as fluorescence photobleaching recovery) were employed to study the transport of hydrophilic fluorescent tracers through complement and perforin pores. By optimizing the confocal effect it was possible to determine the exclusion limit of the pores in situ, i.e. without separation of cells and tracer solution. Single-cell flux measurements by fluorescence microphotolysis yielded information on the sample population distribution of flux rates. By these means a direct comparison of complement and perforin pores was made in sheep erythrocyte membranes. In accordance with previous studies employing a variety of different techniques complement pores were found to have a functional radius of approx. 50 A when generated at high complement concentrations. The flux rate distribution indicated that pore size heterogeneity was rather small under these conditions. Perforin pores, generated in sheep erythrocyte membranes at high perforin concentrations, were found to have a functional size very similar to complement pores. Furthermore, the functional size of the perforin pore seemed to be relatively independent of the dynamic properties of the target membrane since in two cell membranes which are very different in this regard, the human erythrocyte membrane and the plasma membrane of erythroleukemic cells, the functional radius of the perforin pore was also close to 50 A. A perforin-specific antibody reduced the functional radius of perforin pores to 45 A.
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Affiliation(s)
- H Sauer
- Max-Planck-Institut für Biophysik, Frankfurt, F.R.G
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Schröder G, Brandenburg K, Brade L, Seydel U. Pore formation by complement in the outer membrane of gram-negative bacteria studied with asymmetric planar lipopolysaccharide/phospholipid bilayers. J Membr Biol 1990; 118:161-70. [PMID: 2266547 DOI: 10.1007/bf01868473] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The interaction of complement with an asymmetric planar lipopolysaccharide/phospholipid bilayer system as a model for the lipid matrix of the outer membrane of Gram-negative bacteria has been studied. The addition of whole human serum to the aqueous solution at the lipopolysaccharide side of the asymmetric membrane resulted in a rapid increase of the bilayer conductance in discrete steps, indicating the formation of transmembrane pores, which were not observed in the case of pure phospholipid membranes. The amplitudes of the discrete conductance steps varied over a range of more than one order of magnitude. The mean single step conductance was (0.39 +/- 0.24) nS for a subphase containing (in mM): 100 KCl, 5 MgCl2 and 5 HEPES buffer. The steps were grouped into bursts of typically 9 +/- 3 events per burst and the conductance change within one burst was (8.25 +/- 4.00) nS. The pore-forming activity of serum at the asymmetric membrane system was independent of the presence of specific antibodies against the lipopolysaccharide but was dependent on calcium ions. Furthermore, the pore-forming activity required complement component C9. A model for the mode of pore formation by complement is proposed: The complement pore is generated in discrete steps by insertion of C9 monomers into the membrane and their irreversible aggregation to water-filled channels with a diameter of approximately 7 nm assuming a circular geometry.
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Affiliation(s)
- G Schröder
- Forschungsinstitut Borstel, Federal Republic of Germany
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Abstract
The assembly of complement (C) components C5b-9 in membranes results in the formation of transmembrane lesions. The C9 component has been shown to be mainly responsible for formation of the ultrastructurally visible tubules associated with C5b-9 complexes. Several studies have disputed the role of C9 polymerization in C-mediated cytolysis on the grounds that C5b-9 lyses cells in the absence of tubular formation. Here, C5b-9 complexes were reconstituted into high-impedance planar lipid bilayers and shown to form channels which are heterogenous in size. The smallest channels had unitary conductances of 15 picoSiemens (pS) in 0.1 M NaCl. The closing of these channels showed voltage-dependence at membrane potentials exceeding 40 mV. These channels were more cation-selective, with K+ ions being favored over Na+. The 15-pS channels described here are much smaller than the channels attributed previously to either C5b-9 or polymerized C9 complexes but resemble channels formed by the C9b fragment, which does not polymerize into tubules. These results indicate that C5b-9 complexes are capable of damaging membranes by forming initially small ion channels which then aggregate in the membrane to form tubular lesions with much larger conductances. Like C5b-9, C5b-8 also increased membrane permeability. However, this increase in membrane conductance could not be resolved into single channels, suggesting that C5b-8 may induce membrane leakiness by perturbing the packing of membrane lipids, whereas addition of C9 results in authentic production of ion channels.
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Affiliation(s)
- J D Young
- Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York, NY 10021
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Young JD, Cohn ZA. Cellular and humoral mechanisms of cytotoxicity: structural and functional analogies. Adv Immunol 1987; 41:269-332. [PMID: 2891261 DOI: 10.1016/s0065-2776(08)60033-4] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
MESH Headings
- Animals
- Antibody-Dependent Cell Cytotoxicity
- Antigens, Differentiation, T-Lymphocyte/physiology
- CD3 Complex
- Cell Line
- Cell Membrane/physiology
- Colloids
- Complement Membrane Attack Complex
- Complement System Proteins/immunology
- Cytoplasmic Granules/physiology
- Cytotoxicity Tests, Immunologic
- Cytotoxicity, Immunologic
- Cytotoxins/metabolism
- Entamoeba histolytica/physiology
- Enzymes/physiology
- Exocytosis
- Graft Rejection
- Immunity, Cellular
- Immunologic Surveillance
- Ion Channels
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Lymphotoxin-alpha/physiology
- Membrane Glycoproteins
- Membrane Proteins/physiology
- Osmotic Pressure
- Peptides/physiology
- Perforin
- Pore Forming Cytotoxic Proteins
- Protozoan Proteins
- Receptors, Antigen, T-Cell/physiology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
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Affiliation(s)
- J D Young
- Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York, New York 10021
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Young JD, Cohn ZA, Podack ER. The ninth component of complement and the pore-forming protein (perforin 1) from cytotoxic T cells: structural, immunological, and functional similarities. Science 1986; 233:184-90. [PMID: 2425429 DOI: 10.1126/science.2425429] [Citation(s) in RCA: 221] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The ninth component of complement (C9) and the pore-forming protein (PFP or perforin) from cytotoxic T lymphocytes polymerize to tubular lesions having an internal diameter of 100 A and 160 A, respectively, when bound to lipid bilayers. Polymerized C9, assembled by slow spontaneous or rapid Zn2+-induced polymerization, and polyperforin, which is assembled only in the presence of Ca2+, constitute large aqueous pores that are stable, nonselective for solutes, and insensitive to changes of membrane potential. Monospecific polyclonal antibodies to purified C9 and PFP show cross-reactivity, suggesting structural homology between the two molecules. The structural and functional homologies between these two killer molecules imply an active role for pore formation during cell lysis.
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Shiver JW, Dankert JR, Donovan JJ, Esser AF. The ninth component of human complement (C9). Functional activity of the b fragment. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67560-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Benz R, Schmid A, Wiedmer T, Sims PJ. Single-channel analysis of the conductance fluctuations induced in lipid bilayer membranes by complement proteins C5b-9. J Membr Biol 1986; 94:37-45. [PMID: 2433454 DOI: 10.1007/bf01901011] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Single-channel analysis of electrical fluctuations induced in planar bilayer membranes by the purified human complement proteins C5b6, C7, C8, and C9 have been analyzed. Reconstitution experiments with lipid bilayer membranes showed that the C5b-9 proteins formed pores only if all proteins were present at one side of the membrane. The complement pores had an average single-channel conductance of 3.1 nS at 0.15 M KCl. The histogram of the complement pores suggested a substantial variation of the size of the single channel. The linear relationship between single-channel conductance at fixed ionic strength and the aqueous mobility of the ions in the bulk aqueous phase indicated that the ions move inside the complement pore in a manner similar to the way they move in the aqueous phase. The minimum diameter of the pores as judged from the conductance data is approximately 3 nm. The complement channels showed no apparent voltage control or regulation up to transmembrane potentials of 100 mV. At neutral pH the pore is three to four times more permeable for alkali ions than for chloride, which may be explained by the existence of fixed negatively charged groups in or near the pore. The significance of these observations to current molecular models of the membrane lesion formed by these cytolytic serum proteins is considered.
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Thompson M, Krull UJ, Bendell-Young LI. 711—Surface aggregate modulation of lipid membrane ion permeability. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0302-4598(84)87030-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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O'Boyle KP, Siddiqi FA, Tien HT. Antigen-antibody-complement reaction studies on micro bilayer lipid membranes. IMMUNOLOGICAL COMMUNICATIONS 1984; 13:85-103. [PMID: 6086499 DOI: 10.3109/08820138409025453] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The ion permeability of lipid membranes formed on Millipore and Nuclepore filters has been found to exhibit stepwise reductions in electrical resistance in the presence of Forssman antigen, appropriate antiserum and complement. The results appear to support the "hydrophobic doughnut" or transmembrane channel hypothesis, which envisions several polypeptide chains anchoring from more than one terminal complement component to interact with one another within the lipid bilayer. Channel formation in these artificial membranes is believed to be due to the insertion of complement proteins. Concentrations and temperature studies were carried out to ascertain that the electrical responses were owing to the generation of stable channels by complement across the membrane. The diameter of these channels was estimated to be in the order of 100 A.
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Ramm LE, Whitlow MB, Mayer MM. Size distribution and stability of the trans-membrane channels formed by complement complex C5b-9. Mol Immunol 1983; 20:155-60. [PMID: 6302478 DOI: 10.1016/0161-5890(83)90126-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We have performed double marker sieving experiments with molecules ranging from ca. 0.5-3 nm dia. in order to evaluate the size distribution of the channels formed by complement in resealed sheep erythrocyte ghosts. Evidence is presented that marker release through the channels reached equilibrium between the ghosts and the extracellular fluid in a period of 3 hr and that the channels are stable at 37 degrees C for this period of time. Under these experimental conditions we have observed a differential in the endpoint release of inositol and sucrose, which indicates that some of the ghosts carried channels measuring between 0.7 and 0.9 nm dia. No differential was observed between release of sucrose and raffinose (0.9 and 1.1 nm mol. dia., respectively). Comparisons between sucrose and inulin (0.9 and 3 nm mol. dia, respectively) showed a difference in marker release. Also, there was substantial release of inulin, indicating the presence of channels above 3 nm in dia. Hence, the present data indicate formation of channels in three size ranges, namely, 0.7-0.9 nm, 0.9-3 nm and greater than 3 nm.
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Jackson MB, Stephens CL, Lecar H. Single channel currents induced by complement in antibody-coated cell membranes. Proc Natl Acad Sci U S A 1981; 78:6421-5. [PMID: 6273870 PMCID: PMC349051 DOI: 10.1073/pnas.78.10.6421] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An extracellular patch electrode was used to record ionic currents from individual complement-induced channels in the membranes of antibody-coated skeletal muscle. The amplitude of the single-channel currents leads to an estimate of 90 pS for the unit conductance. The kinetics of channel opening and closing show marked variability and complexity. Channels flicker open and closed repeatedly, indicating that once these lesions form, they undergo rapid structural transitions between discrete conducting and nonconducting states.
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Mountz JD, Tien HT. Bilayer lipid membranes (BLM) study of antigen-antibody interactions. J Bioenerg Biomembr 1978; 10:139-51. [PMID: 555462 DOI: 10.1007/bf00743104] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Previous work of del Castillo and co-workers has shown that bilayer lipid membranes (BLM) can be used as transducers for detection of antigen-antibody reactions. The present experiments extend the previous work by incorporating complement into the BLM system. The results indicate that the antigen-antibody complex or the complement has no ability to affect the BLM system separately, but when carefully combined they will destabilize the BLM as a tool for investigating immunological reactions is suggested.
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Mayer MM, Hammer CH, Michaels DW, Shin ML. Immunologically mediated membrane damage: the mechanism of complement action and the similarity of lymphocyte-mediated cytoxicity. IMMUNOCHEMISTRY 1978; 15:813-31. [PMID: 748181 DOI: 10.1016/0161-5890(78)90115-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Podesta RB, Stallard HE, Evans WS, Lussier PE, Jackson DJ, Mettrick DF. Hymenolepis diminuta: determination of unidirectional uptake rates for nonelectrolytes across the surface "epithelial" membrane. Exp Parasitol 1977; 42:300-17. [PMID: 885210 DOI: 10.1016/0014-4894(77)90087-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Blumenthal R, Weinstein JN, Henkart P. Lipid model membrane studies on immune cytotoxic mechanisms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1977; 84:495-507. [PMID: 302636 DOI: 10.1007/978-1-4684-3279-4_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Tyrrell DA, Heath TD, Colley CM, Ryman BE. New aspects of liposomes. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 457:259-302. [PMID: 793635 DOI: 10.1016/0304-4157(76)90002-2] [Citation(s) in RCA: 287] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Michaels DW, Abramovitz AS, Hammer CH, Mayer MM. Increased ion permeability of planar lipid bilayer membranes after treatment with the C5b-9 cytolytic attack mechanism of complement. Proc Natl Acad Sci U S A 1976; 73:2852-6. [PMID: 1066698 PMCID: PMC430774 DOI: 10.1073/pnas.73.8.2852] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The ion permeability of planar lipid bilayers, as measured electrically, was found to increase modestly upon treatment with purified complement complex C5b,6 and complement components C7 and C8. The subsequent addition C9 greatly amplified this change. No permeability changes occurred when components were added individually to the membrane, or when they were used in paired combinations, or when C5b, C7, C8, and C9 were admixed prior to addition. Thus, there is a significant parallel between the permeability changes induced in the model membrane and damage produced in biological membranes by the C5b-9 complement attack sequence. The efficiency of membrane action by C5b-9 was critically dependent on the order in whcih components were added to the membrane. There were also differences in the electrical properties of membranes treated with C5b-8 and C5b-9, though in both cases the enhanced bilayer permeability is best attributed to the formation of trans-membrane channels. Collectively, the data are consistent with the hypothesis that the mechanism of membrane action by complement involves the production of a stable channel across the lipid bilayer, resulting in cell death by colloid-osmotic lysis.
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