The Fine Structure of Neisseria meningitidis Lipooligosaccharide from the M986 Strain and Three of Its Variants

Tsai, Chao-Ming; Jankowska-Stephens, Ewa; Rahman, Mizanur; Cipollo, John F.

doi:10.1074/jbc.m808209200

Cited by 15 publications

(13 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our recent work with a large group of carrier and disease-causing strains of N. meningitidis showed that lipid A phosphorylation states can also be correlated with clinical outcomes [13]. The inset above Figure 1a shows a proposed structure for the major LOS species at m/z 4087.76 in N. meningitidis 89I that represents a prototypical Neisserial LOS structure [9,[46][47][48]. The detailed lipid A and oligosaccharide structures depicted for the N. meningitidis 89I LOS, an L4 immunotype [49], are based on MS and NMR studies of the conserved Neisserial lipid A [50] and the L4 oligosaccharide [42].…”

Section: Molecular Weight Profiling Of Intact Losmentioning

confidence: 99%

Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

Phillips

John

Jarvis

2016

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

LOS MALDI IMS-MSAbstract. Lipooligosaccharides (LOS) are major microbial virulence factors displayed on the outer membrane of rough-type Gram-negative bacteria. These amphipathic glycolipids are comprised of two domains, a core oligosaccharide linked to a lipid A moiety. Isolated LOS samples are generally heterogeneous mixtures of glycoforms, with structural variability in both domains. Traditionally, the oligosaccharide and lipid A components of LOS have been analyzed separately following mild acid hydrolysis, although important acid-labile moieties can be cleaved. Recently, an improved method was introduced for analysis of intact LOS by MALDI-TOF MS using a thin layer matrix composed of 2,4,6-trihydroxyacetophenone (THAP) and nitrocellulose. In addition to molecular ions, the spectra show in-source Bprompt^fragments arising from regiospecific cleavage between the lipid A and oligosaccharide domains. Here, we demonstrate the use of traveling wave ion mobility spectrometry (TWIMS) for IMS-MS and IMS-MS/MS analyses of intact LOS from Neisseria spp. ionized by MALDI. Using IMS, the singly charged prompt fragments for the oligosaccharide and lipid A domains of LOS were readily separated into resolved ion plumes, permitting the extraction of specific subspectra, which led to increased confidence in assigning compositions and improved detection of less abundant ions. Moreover, IMS separation of precursor ions prior to collision-induced dissociation (CID) generated time-aligned, clean MS/MS spectra devoid of fragments from interfering species. Incorporating IMS into the profiling of intact LOS by MALDI-TOF MS exploits the unique domain structure of the molecule and offers a new means of extracting more detailed information from the analysis.

show abstract

Section: Molecular Weight Profiling Of Intact Losmentioning

confidence: 99%

Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

Phillips

John

Jarvis

2016

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…OS Compositions-A number of groups, including our own, have studied the structure of the OS from N. meningitidis (1, 23, 24,26,32,33). Compositions for the OS were assigned based on peaks we detected, the previously reported structures, and using the following potential components: 2 Kdo, 2 Hep, 1 or more Hex, and 1 or more HexNAc, 0 -1 Neu5Ac, 0 -1 O-Ac, 0 -1 O-Gly, and 0 -2 PEA.…”

Section: Relative Abundance Of Lipid a Phosphoforms Correlates With Tmentioning

confidence: 99%

Lipooligosaccharide Structures of Invasive and Carrier Isolates of Neisseria meningitidis Are Correlated with Pathogenicity and Carriage

John

Phillips²,

Din

et al. 2016

Journal of Biological Chemistry

View full text Add to dashboard Cite

The degree of phosphorylation and phosphoethanolaminylation of lipid A on neisserial lipooligosaccharide (LOS), a major cell-surface antigen, can be correlated with inflammatory potential and the ability to induce immune tolerance in vitro. On the oligosaccharide of the LOS, the presence of phosphoethanolamine and sialic acid substituents can be correlated with in vitro serum resistance. In this study, we analyzed the structure of the LOS from 40 invasive isolates and 25 isolates from carriers of Neisseria meningitidis without disease. Invasive strains were classified as groups 1-3 that caused meningitis, septicemia without meningitis, and septicemia with meningitis, respectively. Intact LOS was analyzed by high resolution matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Prominent peaks for lipid A fragment ions with three phosphates and one phosphoethanolamine were detected in all LOS analyzed. LOS from groups 2 and 3 had less abundant ions for highly phosphorylated lipid A forms and induced less TNF-␣ in THP-1 monocytic cells compared with LOS from group 1. Lipid A from all invasive strains was hexaacylated, whereas lipid A of 6/25 carrier strains was pentaacylated. There were fewer O-acetyl groups and more phosphoethanolamine and sialic acid substitutions on the oligosaccharide from invasive compared with carrier isolates. Bioinformatic and genomic analysis of LOS biosynthetic genes indicated significant skewing to specific alleles, dependent on the disease outcome. Our results suggest that variable LOS structures have multifaceted effects on homeostatic innate immune responses that have critical impact on the pathophysiology of meningococcal infections.Our previous studies of neisserial lipooligosaccharide (LOS) 2 and the human innate immune system have shown that the degree of phosphorylation of the lipid A component is correlated with the potential of the LOS to induce inflammation stimulated by innate immunity as revealed by cytokine induction in human monocytes in vitro and, in general, with the severity of infections (1-3). In the LOS of Neisseria meningitidis, the modification of lipid A with phosphoethanolamine (PEA) also has been shown to inhibit the bactericidal activity of cathepsin G within neutrophil extracellular traps (4) and to increase adhesion of the bacteria to human cells (5). Expression of PEA on the oligosaccharide (OS) of meningococcal LOS (Fig. 1), particularly in the O-3 position on heptose (Hep) II, or expression of sialic acid (Neu5Ac) have been shown to inhibit activation of complement via the classical and alternative pathways (6 -9). In this study, we postulated that analysis of the structures of the LOS and the genomic diversity of genes for LOS biosynthesis would reveal differences associated with the severity of meningococcal infection and with carrier versus invasive strains of N. meningitidis.To ascertain whether such differences exist, we characterized the structures of LOS from isolates from infected patients or from carriers of N. meningitidi...

show abstract

“…It is anchored in the outer bacterial membrane by lipid A, and two heptoses (Hep I and Hep II) branch from KDO I (2-keto-3-deoxyoctulosonic acid) carrying the short oligosaccharide side chains (47,70). A structural model of the LPS of the N. meningitidis strain MC58 (serogroup B, ST-32, immunotype L3) integrating recent research and nuclear magnetic resonance (NMR) analysis (28,47,50,66,75) is depicted in Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

The Transcriptional Repressor FarR Is Not Involved in Meningococcal Fatty Acid Resistance Mediated by the FarAB Efflux Pump and Dependent on Lipopolysaccharide Structure

Schielke

Schmitt

Spatz

et al. 2010

Appl Environ Microbiol

View full text Add to dashboard Cite

Free fatty acids are important antimicrobial substances regulating the homeostasis of colonizing bacteria on epithelial surfaces. Here, we show that meningococci express a functional farAB efflux pump, which is indispensable for fatty acid resistance. However, other than in Neisseria gonorrhoeae, the transcriptional regulator FarR is not involved in regulation of this operon in Neisseria meningitidis. We tested the susceptibility of 23 meningococcal isolates against saturated and unsaturated long-chain fatty acids, proving that meningococci are generally highly resistant, with the exception of serogroup Y strains belonging to sequence type 23. Using genetically determined lipopolysaccharide (LPS)-truncated mutant strains, we show that addition of the LPS core oligosaccharide and hexa-acylation of its membrane anchor lipid A are imperative for fatty acid resistance of meningococci. The sensitivity of the serogroup Y strains is due to naturally occurring mutations within the lpxL1 gene, which is responsible for addition of the sixth acyl chain on the LPS membrane anchor lipid A. Therefore, fatty acid resistance in meningococci is provided by both the active efflux pump FarAB and by the natural permeability barrier of the Gram-negative outer membrane. The transcriptional regulator FarR is not implicated in fatty acid resistance in meningococci, possibly giving rise to a constitutively active FarAB efflux pump system and thus revealing diverse mechanisms of niche adaptation in the two closely related Neisseria species.Although humans are physiologically colonized by a vast number of microorganisms, invasion of this microflora is efficiently prevented by dermal and mucosal epithelia which form the barriers of the human body. Homeostasis of the colonizing microflora at these barriers is maintained by numerous mechanisms that include the secretion of antimicrobial compounds by the epithelia. Among these compounds are free fatty acids, which act as nonselective antimicrobials against a broad range of microorganisms. Sebaceous glands, producing a mixture of lipids called sebum, are present in the skin, the nasal epithelium, and the oral epithelium of most adults (62, 71). The produced sebum consists mainly of triglycerides which undergo hydrolysis by both host and bacterial lipases to produce free fatty acids (9). In human saliva, lipid content is about 4 to 20 mg/100 ml and includes both saturated (mainly palmitic and stearic acid) and unsaturated (mainly oleic, linoleic, palmitoleic, arachidonic, and docosahexaenoic acid) fatty acids (59, 65). Similarly, fatty acids form a major constituent of vaginal secretions (45). In most cases bacterial susceptibility to free fatty acids depends on organization of the cell wall, with Gram-negative bacteria being more resistant than Grampositive bacteria (72). Enterobacteriaceae are shielded by their lipopolysaccharide (LPS) from the antimicrobial activity of medium-and long-chain fatty acids (58). Neisseria meningitidis and Neisseria gonorrhoeae are closely related Gram-negative s...

show abstract

The Fine Structure of Neisseria meningitidis Lipooligosaccharide from the M986 Strain and Three of Its Variants

Cited by 15 publications

References 45 publications

Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

Analysis of Bacterial Lipooligosaccharides by MALDI-TOF MS with Traveling Wave Ion Mobility

Lipooligosaccharide Structures of Invasive and Carrier Isolates of Neisseria meningitidis Are Correlated with Pathogenicity and Carriage

The Transcriptional Repressor FarR Is Not Involved in Meningococcal Fatty Acid Resistance Mediated by the FarAB Efflux Pump and Dependent on Lipopolysaccharide Structure

Contact Info

Product

Resources

About