A comparison of the effects of verocytotoxin-1 on primary human renal cellcultures

Infection with verocytotoxin-producing Escherichia coli causes haemolytic u raemic syndrome (HUS). Verocytotoxin-1 (VT1) is cytopathic to renal microva scular endothelial cells in culture, supporting the hypothesis that the vas culopathy of HUS is caused directly by the toxic action of VT1 on cells. We provide evidence that VT1 inhibits protein synthesis in primary cultures o f glomerular epithelial cells (GE), cortical tubular epithelial cells (CTE) and mesangial cells (MC). Using 100 pg/ml of VT1 we saw a decrease in prot ein synthesis to 14.3 +/- 1.9% in vero cells (a primate cell line), 1.7 +/- 0.3% in GE, 0.9 +/- 0.4% in CTE and 74.8 +/- 1.3% in MC at 24 h. The human renal epithelial cells are at least as sensitive as vero cells to the prot ein synthesis inhibitory effects of VT1 if not more so. Cell viability decr eased in all cultures as measured by MTT reduction, neutral red incorporati on and lactate dehydrogenase release and followed the same pattern of susce ptibility as for protein synthesis inhibition. However, unlike vero cells, death occurred without DNA fragmentation. Cell sensitivity was greatest in cells which bound more VT1. (C) 1999 Elsevier Science Ireland Ltd. All righ ts reserved.