Post-diarrheal hemolytic uremic syndrome (HUS) is the leading cause of acute renal failure in children. The HUS is characterized by acute renal injury, microangiopathic hemolytic anemia, and thrombocytopenia. Renal damage predominantly involves glomerular endothelial cell swelling and detachment, fibrin accumulation, and thrombosis. Marked decreases in glomerular filtration rate (GFR) can occur without obvious histologic changes, suggesting augmented vasoconstrictor influence. The HUS is typically associated with enteric infection by shiga-like toxin (SLT) producing Escherichia coli. The toxin binds to a cell surface glycosphingolipid, GB3, is internalized, and inhibits protein synthesis. The above observations, taken together with the finding that SLT is toxic for endothelial cells, have let to the belief that SLT damage to human glomerular endothelial cells (HGEN) is central to the pathogenesis of HUS renal disease. However, little is known about how SLT interacts with glomerular endothelial cells, particularly in humans. Further, little is known about why HGEN appears to be a major target of SLT, or other factors, in HUS. We have developed a new method for studying HGEN. The current application will take advantage of this technique in order to address the above issues. Finally, very little is know about the molecular biologic events that control cell sensitivity to SLT. The current project includes studies that provide crucial information about this process. Accordingly, the specific aims are: 1) development of a human glomerular endothelial cell model to study the biologic actions of SLT; 2) determination of HGEN susceptibility to SLT toxicity including measurement of baseline GB3 expression by HGEN, identification of inflammatory factors regulating HGEN SLT sensitivity, and elucidation of paracrine and autocrine regulation of HGEN SLT sensitivity; 3) determination of the biologic effects of SLT and inflammatory factors on HGEN including evaluation of factors mediating SLT-induced HGEN detachment, examination of SLT modulation of HGEN-regulated fibrin accumulation, and analysis of inflammatory factor and SLT effects on HGEN vasoactive mediator production; and 4) cloning of the gene encoding human UDP-galactose: lactosylceramide alpha 1-4-galactosyl-transferase, the rate-limiting enzyme in GB3 formation. These studies provide essential information on how and why HGEN are damaged in HUS.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
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Special Emphasis Panel (SRC (01))
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Hirschman, Gladys H
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University of Utah
Internal Medicine/Medicine
Schools of Medicine
Salt Lake City
United States
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Stricklett, Peter K; Hughes, Alisa K; Kohan, Donald E (2005) Inhibition of p38 mitogen-activated protein kinase ameliorates cytokine up-regulated shigatoxin-1 toxicity in human brain microvascular endothelial cells. J Infect Dis 191:461-71
Ergonul, Zuhal; Hughes, Alisa K; Kohan, Donald E (2003) Induction of apoptosis of human brain microvascular endothelial cells by shiga toxin 1. J Infect Dis 187:154-8
Ergonul, Zuhal; Clayton, Frederic; Fogo, Agnes B et al. (2003) Shigatoxin-1 binding and receptor expression in human kidneys do not change with age. Pediatr Nephrol 18:246-53
Hughes, Alisa K; Schmid, Douglas I; Kohan, Donald E (2002) Sex steroids do not affect shigatoxin cytotoxicity on human renal tubular or glomerular cells. BMC Nephrol 3:6
Hughes, Alisa K; Ergonul, Zuhal; Stricklett, Peter K et al. (2002) Molecular basis for high renal cell sensitivity to the cytotoxic effects of shigatoxin-1: upregulation of globotriaosylceramide expression. J Am Soc Nephrol 13:2239-45
Stricklett, Peter K; Hughes, Alisa K; Ergonul, Zuhal et al. (2002) Molecular basis for up-regulation by inflammatory cytokines of Shiga toxin 1 cytotoxicity and globotriaosylceramide expression. J Infect Dis 186:976-82
Hughes, A K; Stricklett, P K; Kohan, D E (2001) Shiga toxin-1 regulation of cytokine production by human glomerular epithelial cells. Nephron 88:14-23
Schmid, D I; Kohan, D E (2001) Effect of shigatoxin-1 on arachidonic acid release by human glomerular epithelial cells. Kidney Int 60:1026-36
Hughes, A K; Stricklett, P K; Schmid, D et al. (2000) Cytotoxic effect of Shiga toxin-1 on human glomerular epithelial cells. Kidney Int 57:2350-9
Stevens, A L; Breton, S; Gustafson, C E et al. (2000) Aquaporin 2 is a vasopressin-independent, constitutive apical membrane protein in rat vas deferens. Am J Physiol Cell Physiol 278:C791-802

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