Influence of acyl chain fluidity on the lipopolysaccharide-induced activation of complement

Wiese, Andre; Grunewald, P; Schaper, Klaus‐Jürgen; Seydel, Ulrich

doi:10.1177/09680519010070020901

Cited by 7 publications

(5 citation statements)

References 43 publications

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“…It has been shown earlier that an increase in membrane fluidity increases the formation of lytic membrane pores by the complement system (27). However, this parameter cannot explain the positive correlation between pore formation and the length of the core sugar moiety, because membrane fluidity varies only slightly for the LPS used in the present investigation (28).…”

Section: Fig 5 Mean Number Of Porescontrasting

confidence: 45%

Pore Formation and Function of Phosphoporin PhoE of Escherichia coli Are Determined by the Core Sugar Moiety of Lipopolysaccharide

Hagge

Cock

Gutsmann

et al. 2002

Journal of Biological Chemistry

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The lipid matrix of the outer membrane of Gram-negative bacteria is an asymmetric bilayer composed of a phospholipid inner leaflet and a lipopolysaccharide outer leaflet. Incorporated into this lipid matrix are, among other macromolecules, the porins, which have a sieve-like function for the transport or exclusion of hydrophilic substances. It is known that a reduced amount of porins is found in the outer membrane of rough mutants as compared with wild-type bacteria. This observation was discussed to be caused by a reduced number of insertion sites in the former. We performed electrical measurements on reconstituted planar bilayers composed of lipopolysaccharide on one side and a phospholipid mixture on the other side using lipopolysaccharide from various rough mutant strains of Salmonella enterica serovar Minnesota. We found that pore formation by PhoE trimers that were added to the phospholipid side of the bilayers increased with the increasing length of the lipopolysaccharide core sugar moiety. These results allow us to conclude that the length of the sugar moiety of lipopolysaccharide is the parameter governing pore formation and that no particular insertion sites are required. Furthermore, we found that the voltage gating of the porin channels is strongly dependent on the composition of the lipid matrix.The cell envelope of Gram-negative bacteria consists of the cytoplasmic membrane, the peptidoglycan layer, and an additional barrier, the outer membrane (OM), 1 (1) which is strictly asymmetric with respect to its lipid composition. Whereas the inner membrane (IM) is composed on both sides of phospholipids, the OM consists of a phospholipid inner leaflet and a lipopolysaccharide (LPS) outer leaflet. The LPS consists of an oligo-or polysaccharide portion covalently linked to a lipid component termed lipid A, which anchors the molecule in the membrane (2). In wild-type strains, the polysaccharide portion consists of an O-specific chain and the core oligosaccharide. Rough mutant strains do not express the O-specific chain, but retain core oligosaccharides of varying length. The LPS of various rough mutants are characterized by chemotypes in a sequence of decreasing length of the core sugar as Ra (complete core), Rb, Rc, Rd, and Re. Deep-rough LPS (Re LPS) represents the minimal structure of LPS consisting of only lipid A and two 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) monosaccharides (3) (Fig. 1).The OM protects the cell from harmful agents like antibiotics and toxins and against changes in osmotic pressure. Transmembrane proteins, the porins, allowing the uptake and disposal of small hydrophilic compounds such as nutrients and waste products (4), are assembled in the OM. In Escherichia coli OmpF and OmpC represent the general diffusion pores. The phosphoporin PhoE is synthesized when cells are grown under phosphate limitation (5). PhoE has a molecular weight of M r 36,822 and an exclusion size of M r ϳ600 and is weakly anion selective (6). The crystal structure of PhoE has been solved (7). The channel-formin...

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Section: Fig 5 Mean Number Of Porescontrasting

confidence: 45%

Pore Formation and Function of Phosphoporin PhoE of Escherichia coli Are Determined by the Core Sugar Moiety of Lipopolysaccharide

Hagge

Cock

Gutsmann

et al. 2002

Journal of Biological Chemistry

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“…This, coupled with data indicating that decreased LPS acylation results in increased membrane permeability in phospholipid bilayers, suggests a model in which the addition of an acyl group to the lipid A region increases the rigidity of the membrane, thus decreasing the susceptibility to lysis by various immune mechanisms (21).…”

Section: Discussionmentioning

confidence: 93%

“…This suggests that the lipid A acylation state may influence outer membrane permeability. In addition, changes in lipid A acylation have been shown to affect complement activation and opsonization, as well as TLR-4 recognition in vitro (1,7,13,21). Despite these compelling data, the influence of lipid A acylation on in vivo host-pathogen interactions is not well understood.…”

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confidence: 94%

pagPIs Required for Resistance to Antibody-Mediated Complement Lysis duringBordetella bronchisepticaRespiratory Infection

Pilione

Pishko²,

Preston

et al. 2004

Infect Immun

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To efficiently colonize and persist in the lower respiratory tract, bacteria must survive multiple host immune mechanisms. Bordetella bronchiseptica is a gram-negative respiratory pathogen that naturally infects mice and persists in the lower respiratory tract for up to 49 days postinoculation. In this work, we examined the effect of mutation of the pagP gene on the persistence of B. bronchiseptica in the lower respiratory tract of mice. The pagP gene encodes a palmitoyl transferase that is responsible for the addition of a palmitoyl group to the lipid A region of B. bronchiseptica lipopolysaccharide. Data presented here confirm that a B. bronchiseptica ⌬pagP mutant demonstrates defective persistence in the lower respiratory tract of wild-type mice. We hypothesized that the defective persistence of the B. bronchiseptica ⌬pagP mutant was due to an increased susceptibility of this mutant to a host immune response. In vivo data indicate that both B cells and the complement component C3 are required for the reduced bacterial numbers of the ⌬pagP mutant on day 14 postinoculation. In addition, an in vitro complement killing assay demonstrated that B. bronchiseptica exhibits pagP-dependent resistance to antibody-mediated complement killing at low concentrations of immune serum. Taken together, these results suggest that pagP is required for B. bronchiseptica to resist antibody-mediated complement lysis during respiratory infection.

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“…We could on the one hand determine the activation pathway and on the other hand investigate the influence of the lipid matrix on the pore size. 27,66,67 Whereas no changes in electrical conductance were detected when serum was added to the PL side of the membrane, serum addition to the LPS side (Re LPS from Salmonella enterica sv. Minnesota or Escherichia coli) led to an increase in membrane conductance.…”

Section: Complementmentioning

confidence: 99%

“…This correlation was also shown to hold for the susceptibility of a respective pair of rough mutant strains towards human serum. 67 The influence of fluidity on complement activation has been discussed controversially so far; however, the data have been derived from systems which did not closely resemble the outer membrane. 69,70 In studies aimed at the elucidation of the pathways of complement activation, we found that neither the Ca 2+chelator EGTA nor the depletion of C1q had an influence on the activation by GSL-1, whereas in the case of Re LPS a significant de-activation was observed.…”

Section: Complementmentioning

confidence: 99%

Review: Towards antibacterial strategies: studies on the mechanisms of interaction between antibacterial peptides and model membranes

Wiese

Gutsmann

Seydel

2003

Journal of Endotoxin Research

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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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Influence of acyl chain fluidity on the lipopolysaccharide-induced activation of complement

Cited by 7 publications

References 43 publications

Pore Formation and Function of Phosphoporin PhoE of Escherichia coli Are Determined by the Core Sugar Moiety of Lipopolysaccharide

Pore Formation and Function of Phosphoporin PhoE of Escherichia coli Are Determined by the Core Sugar Moiety of Lipopolysaccharide

pagPIs Required for Resistance to Antibody-Mediated Complement Lysis duringBordetella bronchisepticaRespiratory Infection

Review: Towards antibacterial strategies: studies on the mechanisms of interaction between antibacterial peptides and model membranes

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