Interaction of Shiga toxins with human brain microvascular endothelial cells: Cytokines as sensitizing agents

Neurologic abnormalities are among the most serious extraintestinal complic ations of infection with Shiga toxin (Stx)-producing bacteria. Histopatholo gic examination of tissues from patients with extraintestinal sequelae sugg ested that Stxs damage endothelial cells. It is shown here that human brain microvascular endothelial cells (HBMECs) are relatively resistant to purif ied Stxs (50% cytotoxic doses [CD(50)s] greater than or equal to 10 mu g/mL ). Pretreatment of HBMECs with tumor necrosis factor (TNF)-alpha, interleuk in (IL)-1 beta, n-butyric acid, or a cAMP analogue resulted in a 10(3)- to 10(4)-fold decrease in CD50 values and a 2- to 4-fold increase in fluoresce inated Stx binding to HBMECs, Treatment of HBMECs with lipopolysaccharides did not significantly alter cytotoxicity or toxin binding. TNF-alpha and IL -1 beta treatment was associated with the increased HBMEC expression of the toxin-binding glycolipid globotriaosylceramide. HBMECs did not produce IL- 1 beta and produced only trace amounts of TNF-alpha when stimulated with pu rified Stx1 in vitro.