Flagellin and GroEL mediates in vitro binding of an atypical enteropathogenic Escherichia coli to cellular fibronectin.

Claudia T P Moraes,Sarita S Rossato,Ângela S Barbosa,Waldir P Elias,Fernando H Martins,Mauricio J Farfan,Juliana M Polatto,Danielle D Munhoz,Mariana Izquierdo,Daniel C Pimenta,Roxane M F Piazza

doi:10.1186/s12866-015-0612-4

Claudia T P Moraes, Sarita S Rossato + Show 9 more

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https://doi.org/10.1186/s12866-015-0612-4

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Abstract

BackgroundEnteropathogenic Escherichia coli (EPEC) is distinguished mainly by the presence of EPEC adherence factor plasmid (pEAF) in typical EPEC (tEPEC) and its absence in atypical EPEC (aEPEC). The initial adherence to the intestinal mucosa is complex and mediated by adhesins other than bundle-forming pilus, which is not produced by aEPEC. Extracellular matrix (ECM) proteins of eukaryotic cells are commonly recognized by bacterial adhesins. Therefore, binding to ECM proteins may facilitate colonization, invasion and/or signaling by intestinal pathogens. Previous studies from our group demonstrated that aEPEC O26:H11 (strain BA2103) showed high binding activity to fibronectin, not shared by its counterpart, aEPEC O26:HNM.ResultsIn the present study, using mass spectrometry after fibronectin-associated immunoprecipitation, two proteins, flagellin (50 kDa) and GroEL (52 kDa), were identified and BA2103 binding ability to fibronectin was inhibited in the presence of anti-H11 and anti-GroEL sera, but not by either naïve rabbit or other unrelated sera. It was also observed that the presence of purified flagellin inhibits adhesion of BA2103 to cellular fibronectin in a dose-dependent manner. Additionally, BA2103 GroEL is similar to the same protein of uropathogenic E. coli.ConclusionsOur results suggest that flagellin may play a role in the in vitro interaction of BA2103 with cellular fibronectin, and GroEL can be an accessory protein in this process.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-015-0612-4) contains supplementary material, which is available to authorized users.

Highlights

Enteropathogenic Escherichia coli (EPEC) is distinguished mainly by the presence of EPEC adherence factor plasmid in typical EPEC and its absence in atypical EPEC
Our results indicate that flagellin may play a role in the in vitro interaction with this Extracellular matrix (ECM) component, and GroEL can be an accessory protein in this process
Binding of E. coli strains to cellular fibronectin The binding ability of BA2103 to cellular fibronectin was compared to another atypical EPEC (aEPEC) strain, a nonmotile O26 (2271-1/85) and a nonmotile K12 E. coli strain

Summary

Introduction

Enteropathogenic Escherichia coli (EPEC) is distinguished mainly by the presence of EPEC adherence factor plasmid (pEAF) in typical EPEC (tEPEC) and its absence in atypical EPEC (aEPEC). Extracellular matrix (ECM) proteins of eukaryotic cells are commonly recognized by bacterial adhesins. The ability to adhere to extracellular matrix (ECM) proteins has been shown to be essential for the virulence of several pathogens [15]. ECM proteins are commonly recognized by bacterial adhesins and have been shown to act as substrates for bacterial adherence to eukaryotic cells [15, 18,19,20,21,22]. Binding to ECM proteins may facilitate colonization, invasion, and/or signaling by intestinal pathogens [17]. Fibronectin is responsible for connecting the collagen scaffold and other ECM components [22], and was the first eukaryotic cell receptor described for bacteria [18]

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