A Topographical Atlas of Shiga Toxin 2e Receptor Distribution in the Tissues of Weaned Piglets.

Daniel Steil,Robert Bonse,German Vallejo,Johannes Müthing,Gottfried Pohlentz,Helge Karch,Iris Meisen

doi:10.3390/toxins8120357

Abstract

Shiga toxin (Stx) 2e of Stx-producing Escherichia coli (STEC) is the primary virulence factor in the development of pig edema disease shortly after weaning. Stx2e binds to the globo-series glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer, Galα1-4Galβ1-4Glcβ1-1Cer) and globotetraosylceramide (Gb4Cer, GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer), the latter acting as the preferential Stx2e receptor. We determined Stx receptor profiles of 25 different tissues of a male and a female weaned piglet using immunochemical solid phase binding assays combined with mass spectrometry. All probed tissues harbored GSL receptors, ranging from high (category I) over moderate (category II) to low content (category III). Examples of Gb4Cer expression in category I tissues are small intestinal ileum, kidney pelvis and whole blood, followed by colon, small intestinal duodenum and jejunum belonging to category II, and kidney cortex, cerebrum and cerebellum as members of category III organs holding true for both genders. Dominant Gb3Cer and Gb4Cer lipoforms were those with ceramides carrying constant sphingosine (d18:1) and a variable C16:0, C22:0 or C24:1/C24:0 fatty acid. From the mapping data, we created a topographical atlas for Stx2e receptors in piglet tissues and organs, which might be helpful to further investigations on the molecular and cellular mechanisms that underlie infections of Stx2e-producing STEC in pigs and their zoonotic potential for humans.

Highlights

Among the different Shiga toxin (Stx) subtypes released by Stx-producing Escherichia coli (STEC) [1], Stx2e, known as edema disease verotoxin 2e (VT2e) [2], has been identified as the primary virulence factor involved in the pathogenesis of edema disease in pigs [3,4,5]
GSL-containing lipid extracts were prepared from 25 tissues and organs of a male and a female weaned piglet, both six weeks of age, using small-sized samples of less than 1 g of wet weight allowing for comprehensive GSL analysis based on highly sensitive technologies combining mass spectrometry with thin-layer chromatography (TLC) immunostaining
The structures of the various lipoforms of immunopositive GSLs were elucidated by means of electrospray ionization (ESI) mass spectrometry (MS), followed by final receptor verification with TLC overlay assays using Stx2e

Summary

Introduction

Among the different Shiga toxin (Stx) subtypes released by Stx-producing Escherichia coli (STEC) [1], Stx2e, known as edema disease verotoxin 2e (VT2e) [2], has been identified as the primary virulence factor involved in the pathogenesis of edema disease in pigs [3,4,5]. Subtypes Stx2a and Stx1a are the most prominent virulence factors of STEC isolates being responsible for severe gastrointestinal diseases and extraintestinal complications, including hemorrhagic colitis and hemolytic uremic syndrome (HUS) [6,7,8]. Stx2e-producing STEC cause, typically during the first two weeks after weaning, the edema disease, an enterotoxemia characterized by subcutaneous, mesenteric and cerebral edemas with neurological impairment including ataxia, paralysis, and recumbency as main clinical signs [3].

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Conclusion