Dataset Information

The Lipid Raft Proteome of Borrelia burgdorferi.

ABSTRACT: Eukaryotic lipid rafts are membrane microdomains rich in cholesterol that contain a selective set of proteins, and have been associated with multiple biological functions. The Lyme disease agent, Borrelia burgdorferi, is one of an increasing number of bacterial pathogens that incorporates cholesterol onto its membrane, and form cholesterol glycolipid domains that possess all the hallmarks of eukaryotic lipid rafts. In this study, we isolated lipid rafts from cultured B. burgdorferi as a detergent resistant membrane (DRM) fraction on density gradients, and characterized those molecules that partitioned exclusively or are highly enriched in these domains. Cholesterol glycolipids, the previously known raft-associated lipoproteins OspA and OpsB, and cholera toxin partitioned into the lipid rafts fraction indicating compatibility with components of the DRM. The proteome of lipid rafts was analyzed by a combination of LC-MS/MS or MudPIT. Identified proteins were analyzed in silico for parameters that included localization, isoelectric point, molecular mass and biological function. The proteome provided a consistent pattern of lipoproteins, proteases and their substrates, sensing molecules, and prokaryotic homologs of eukaryotic lipid rafts. This study provides the first analysis of a prokaryotic lipid raft and has relevance for the biology of Borrelia, other pathogenic bacteria, as well as for the evolution of these structures.

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Borrelia Burgdorferi B31

TISSUE(S): Prokaryotic Cell

DISEASE(S): Lyme Disease

SUBMITTER: Alvaro Toledo

LAB HEAD: Jorge Benach

PROVIDER: PXD002365 | Pride | 2015-09-21

REPOSITORIES: Pride

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Publications

The lipid raft proteome of Borrelia burgdorferi.

Toledo Alvaro A Pérez Alberto A Coleman James L JL Benach Jorge L JL

Proteomics 20150928 21

Eukaryotic lipid rafts are membrane microdomains that have significant amounts of cholesterol and a selective set of proteins that have been associated with multiple biological functions. The Lyme disease agent, Borrelia burgdorferi, is one of an increasing number of bacterial pathogens that incorporates cholesterol onto its membrane, and form cholesterol glycolipid domains that possess all the hallmarks of eukaryotic lipid rafts. In this study, we isolated lipid rafts from cultured B. burgdorfe ...[more]

PMID: 26256460

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Project description:Progression and relapse-free survival of ovarian carcinoma are associated with the abundance of immunosuppressed CD163highCD206high tumor-associated macrophages (TAMs) and high levels of polyunsaturated fatty acids (PUFAs), in particular arachidonic acid (AA), in the tumor microenvironment. In the present study, we have investigated whether both associations are functionally linked. Methods: The effect of PUFAs on cytokine-mediated pro-inflammatory signal transduction was studied in primary monocyte-derived macrophages (MDMs) by transcriptomics, bioinformatics, phosphoprotein analysis of signal transduction proteins and MS-based proteomics of lipid rafts. Results: Pathway analysis of transcriptional profiles revealed that high CD163 and CD206/MRC1 expression in TAMs is strongly associated with an inhibition of cytokine-triggered signal transduction. This is mirrored by an impairment of the transcriptional response to interferon-beta (IFNbeta), IFNgamma and IL-6 in monocyte-derived macrophages (MDMs) by AA. This AA-mediated inhibition of pro-inflammatory signaling is caused by dysfunctions of the cognate receptors, as indicated by the inhibition by PUFAs of JAK1, JAK2, STAT1 and STAT3 phosphorylation, with the strongest inhibitory effects exerted by AA and its non-metabolizable analog ETYA. AA/ETYA treatment of MDMs results in altered composition of lipid rafts, including reduced amounts of the interferon receptor IFNAR1, STAT1 and other immune-regulatory proteins. The AA-mediated inhibition of IFN-triggered STAT1 phosphorylation was reversed by water-soluble cholesterol, known to prevent the perturbation of lipid raft structure by PUFAs. Conclusion: Our data suggest that AA, and to a lesser degree other PUFAs, impair pro-inflammatory signaling in macrophages, at least in part by altering the structure of lipid rafts, and thereby contribute to the reeducation of tumor-associated macrophages. Our findings also suggest that the pharmacologic restoration of lipid raft functions in TAM may be a promising strategy for the development of new therapeutic approaches.

Project description:Background: Image-based screening improves the detection of early-stage lung adenocarcinoma (LUAD)but also highlights the issue of high false-positive diagnoses, which puts patients at a risk of unnecessary over-treatment. Therefore, more precise discrimination criteria are required to ensure that patients with early-stage LUAD receive appropriate treatments. Methods: we integrated 158 early-stage LUAD cases from 2 independent cohorts, including 30 matched resected specimens with complete radiological and pathological information, and 128 retrospective pathological pair-samples with partial follow-up data. This integration allowed us to conduct a correlation analysis between clinical phenotype and transcriptome landscape. Immunohistochemistry was performed using tissue microarrays to examine the expression of phospholipid phosphatase 2 (PLPP2) and lipid-raft markers. Lipidomics analysis was used to determine the changes of lipid components in PLPP2-overexpressed cells. To assess the effects of PLPP2 on the malignant phenotypes of LUAD cells, we conducted mice tumor-bearing experiments and in vitro cellular experiments by knocking down PLPP2 and inhibiting lipid raft synthesis with MβCD, respectively. Results: Bioinformatics analysis indicated that the co-occurrence of lipid raft formation and rapid cell proliferation might exhibit synergistic effects in driving oncogenesis from lung preneoplasia to adenocarcinoma. The enhanced activation of the cell cycle promoted the transition from non-invasive to invasive status in early-stage LUAD, which was related to an increase in lipid rafts within LUAD cells. PLPP2 participated in lipid raft formation by altering the component contents of lipid rafts, such as esters, sphingomyelin, and sphingosine. Furthermore, elevated PLPP2 levels were identified as an independent prognostic risk factor for LUAD patients. Further results from in vivo and in vitro experiments confirmed that PLPP2 could induce excessive cell proliferation by enhancing lipid raft formation in LUAD cells. Conclusions: Our study has revealed the characteristics of gene expression profiles in early-stage LUAD patients with the different radiological and pathological subtypes, as well as deciphered transcriptomic evolution trajectory from preneoplasia to invasive LUAD. Furthermore, it suggests that PLPP2-mediated lipid raft synthesis may be a significant biological event in the initiation of early-stage LUAD, offering a potential target for more precise diagnosis and therapy in clinical settings.

Dataset Information

The Lipid Raft Proteome of Borrelia burgdorferi.

Publications

The lipid raft proteome of Borrelia burgdorferi.

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