The Shiga Toxin Receptor Globotriaosylceramide as Therapeutic Target in Shiga Toxin E. coli Mediated HUS.

Romy Bouwmeester,Wouter J C Feitz,Christoph Licht,Thea J A M Van Der Velden,Susan Goorden,Nicole C A J Van De Kar,Lambert P J W Van Den Heuvel

doi:10.3390/microorganisms9102157

Abstract

In 90% of the cases, childhood hemolytic uremic syndrome (HUS) is caused by an infection with the Shiga toxin (Stx) producing E. coli bacteria (STEC-HUS). Stx preferentially binds to its receptor, the glycosphingolipid, globotriaosylceramide (Gb3), present on the surface of human kidney cells and various organs. In this study, the glycosphingolipid pathway in endothelial cells was explored as therapeutic target for STEC-HUS. Primary human glomerular microvascular endothelial cells (HGMVECs) and human blood outgrowth endothelial cells (BOECs) in quiescent and activated state were pre-incubated with Eliglustat (Cerdelga®; glucosylceramide synthase inhibitor) or Agalsidase alpha (Replagal®; human cell derived alpha-galactosidase) in combination with various concentrations of Stx2a. Preincubation of endothelial cells with Agalsidase resulted in an increase of α-galactosidase activity in the cell, but had no effect on the binding of Stx to the cell surface when compared to control cells. However, the incubation of both types of endothelial cells incubated with or without the pro-inflammatory cytokine TNFα in combination with Eliglustat resulted in significant decrease of Stx binding to the cell surface, a decrease in protein synthesis by Stx2a, and diminished cellular Gb3 levels as compared to control cells. In conclusion, inhibition of the synthesis of Gb3 may be a potential future therapeutic target to protect against (further) endothelial damage caused by Stx.

Highlights

The most frequent form of hemolytic uremic syndrome (HUS) in childhood is caused by a gastro-intestinal infection with the Shiga toxin (Stx) producing E. coli bacteria (STEC) [1]
Binding of Stx to the endothelial cell surface was determined by flow cytometry in Cell
Binding of Stx to the endothelial cell surface was determined by flow cytometry in measure Gb3 cell surface expression levels (20)

Summary

Introduction

The most frequent form of HUS in childhood is caused by a gastro-intestinal infection with the Shiga toxin (Stx) producing E. coli bacteria (STEC) [1]. For STEC-HUS, characterized by thrombocytopenia, nonimmune hemolytic anemia, and acute kidney failure [2], no specific therapy is yet available [3,4]. The disease can lead to end stage renal disease (ESRD) and has a mortality rate of 2–5% in the acute phase [5]. Long-term renal sequelae like hypertension, proteinuria, and chronic kidney failure are reported in an estimated 25–30% of cases [5]. After intestinal colonization by STEC, Stx is released into the intestinal lumen and translocated to the blood circulation. Various studies have shown that the toxin might bind to blood cells (i.e., leukocytes, red blood cells, and/or platelets) and/or to microvesicles

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