Direct cytotoxic action of Shiga toxin on human vascular endothelial cells

Abstract

To help explain a role of the Shiga toxin family in hemorrhagic colitis and hemolytic-uremic syndrome in humans, it has been hypothesized that these toxins cause direct damage to the vascular endothelium. We now report that Shiga toxin purified from Shigella dysenteriae 1 does indeed have a direct cytotoxic effec on vascular endothelial cells in cultures. Human umbilical vein endothelial cells (HUVEC) in confluent monolayers were reduced 50% by 10-8 M Shiga toxin after a lag period of 48 to 96 h. In comparison, nonconfluent HUVEC were reduced 50% by 10-10 M Shiga toxin within a 24-h period. These data suggest that dividing endothelial cells are more sensitive to Shiga toxin than are quiescent cells in confluent monolayers. Both confluent and nonconfluent HUVEC specifically bound '25I-Shiga toxin. However, in response to the toxin, rates of incorporation of [3H]leucine into protein were more severely reduced in nonconfluent cells than in confluent cells. Toxin inhibition of protein synthesis preceded detachment of cells from the substratum. The specific binding of '251-Shiga toxin to human endothelial cells and the cytotoxic response were both toxin dose dependent and neutralized by anti-Shiga toxin antibody. Heat-denatured Shiga toxin was without the cytotoxic effect. In addition, the complete culture system contained less than 0.1 ng of bacterial endotoxin per ml, as measured by the Limulus amoebocyte lysate test.

Damage to nuclear DNA induced by Shiga toxin 1 and ricin in human endothelial cells1

“…Previous studies have shown that HUVEC are sensitive to the toxic action of Stxs (15,(33)(34)(35). Since besides depurinating RNA 28S within ribosomes, ricin and Stx1 also depurinate DNA in vitro, the rate of protein synthesis of HUVEC treated with the two toxins was measured and the relationship with a possible nuclear DNA damage was investigated.…”

Lipopolysaccharide O-antigen of enterohemorrhagic Escherichia coli O157:H7 is required for killing both insects and mammals

“…Hemolysins are encoded by ehxCABD genes on the plasmid pO157 (Saitoh et al, 2008). These factors damage cultured intestinal epithelial cells (Obrig et al, 1988;Figueiredo et al, 2003). Bacterial motility and adherence to intestinal epithelial cells are considered to contribute to EHEC virulence (Levine et al, 1983;Holden & Gally, 2004).…”

Role of EHEC O157:H7 virulence factors in the activation of intestinal epithelial cell NF-κB and MAP kinase pathways and the upregulated expression of interleukin 8

“…Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is a pathogen that causes diarrhoea, and can result in haemorrhagic colitis and the potentially fatal haemolytic uraemic syndrome (HUS) (Besser et al ., 1999). In contrast to other adherent strains of E. coli , EHEC can produce Shiga toxins (Stxs), which are thought to be important in the pathogenesis of EHEC-induced renal disease and vascular complications of haemorrhagic colitis by direct cytotoxic effects on microvascular cells of the kidney and colonic mucosa (Obrig et al ., 1988;Tesh et al ., 1991).…”