Proteomics characterization of outer membrane vesicles from the extraintestinal pathogenic Escherichia coli DeltatolR IHE3034 mutant.
Extraintestinal pathogenic Escherichia coli are the cause of a diverse spectrum of invasive infections in humans and animals, leading to urinary tract infections, meningitis, or septicemia. In this study, we focused our attention on the identification of the outer membrane proteins of the pathogen in consideration of their important biological role and of their use as potential targets for prophylactic and therapeutic interventions. To this aim, we generated a DeltatolR mutant of the pathogenic IHE3034 strain that spontaneously released a large quantity of outer membrane vesicles in the culture supernatant. The vesicles were analyzed by two-dimensional electrophoresis coupled to mass spectrometry. The analysis led to the identification of 100 proteins, most of which are localized to the outer membrane and periplasmic compartments. Interestingly based on the genome sequences available in the current public database, seven of the identified proteins appear to be specific for pathogenic E. coli and enteric bacteria and therefore are potential targets for vaccine and drug development. Finally we demonstrated that the cytolethal distending toxin, a toxin exclusively produced by pathogenic bacteria, is released in association with the vesicles, supporting the recently proposed role of bacterial vesicles in toxin delivery to host cells. Overall, our data demonstrated that outer membrane vesicles represent an ideal tool to study Gram-negative periplasm and outer membrane compartments and to shed light on new mechanisms of bacterial pathogenesis.
Berlanda Scorza
Francesco
F
Biochemistry and Molecular Biology Unit, Novartis Vaccines and Diagnostics, 53100 Siena, Italy.
Doro
Francesco
F
Rodríguez-Ortega
Manuel José
MJ
Stella
Maria
M
Liberatori
Sabrina
S
Taddei
Anna Rita
AR
Serino
Laura
L
Gomes Moriel
Danilo
D
Nesta
Barbara
B
Fontana
Maria Rita
MR
Spagnuolo
Angela
A
Pizza
Mariagrazia
M
Norais
Nathalie
N
Grandi
Guido
G
D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry* / Q000648:ultrastructure; D004926:Escherichia coli / Q000737:chemistry / Q000166:cytology* / Q000235:genetics* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000235:genetics*; D016680:Genome, Bacterial; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010455:Peptides; D033903:Periplasmic Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits; D040901:Proteomics / Q000379:methods*; D012984:Software
D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D010455:Peptides; D033903:Periplasmic Proteins; D021122:Protein Subunits; C067044:cytolethal distending toxin; C060794:tolR protein, E coli