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Open Access Short Report

Gut proteases target Yersinia invasin in vivo

Janja Trček, Marc F Oellerich, Katy Niedung, Frank Ebel, Sandra Freund and Konrad Trülzsch*

Author Affiliations

Max von Pettenkofer Institut für Hygiene und Medizinische Mikrobiologie, Ludwig Maximilians Universität München, Germany

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BMC Research Notes 2011, 4:129  doi:10.1186/1756-0500-4-129

Published: 18 April 2011

Abstract

Background

Yersinia enterocolitica is a common cause of food borne gastrointestinal disease. After oral uptake, yersiniae invade Peyer's patches of the distal ileum. This is accomplished by the binding of the Yersinia invasin to β1 integrins on the apical surface of M cells which overlie follicle associated lymphoid tissue. The gut represents a barrier that severely limits yersiniae from reaching deeper tissues such as Peyer's patches. We wondered if gut protease attack on invasion factors could contribute to the low number of yersiniae invading Peyer's patches.

Findings

Here we show that invasin is rapidly degraded in vivo by gut proteases in the mouse infection model. In vivo proteolytic degradation is due to proteolysis by several gut proteases such as trypsin, α-chymotrypsin, pancreatic elastase, and pepsin. Protease treated yersiniae are shown to be less invasive in a cell culture model. YadA, another surface adhesin is cleaved by similar concentrations of gut proteases but Myf was not cleaved, showing that not all surface proteins are equally susceptible to degradation by gut proteases.

Conclusions

We demonstrate that gut proteases target important Yersinia virulence factors such as invasin and YadA in vivo. Since invasin is completely degraded within 2-3 h after reaching the small intestine of mice, it is no longer available to mediate invasion of Peyer's patches.