title: Detergent-resistant globotriaosyl ceramide may define verotoxin/glomeruli-restricted hemolytic uremic syndrome pathology.
abstract: Verotoxin binding to its receptor, globotriaosyl ceramide(Gb(3)) mediates the glomerular pathology of hemolytic uremic syndrome, but Gb(3) is expressed in both tubular and glomerular cells. Gb(3) within detergent-resistant membranes, an index of glycolipid-cholesterol enriched lipid rafts, is required for in vitro cytotoxicity. We found that verotoxin 1 and 2 binding to human adult renal glomeruli is detergent resistant, whereas the strong verotoxin binding to renal tubules is detergent sensitive. Verotoxin binding to pediatric glomeruli was detergent resistant but binding to adult glomeruli was enhanced, remarkably for some samples, by detergent extraction. Detergent-sensitive glomerular components may provide age-related protection against verotoxin glomerular binding. Mouse glomeruli remained verotoxin unreactive after detergent extraction, whereas tubular binding was lost. Cholesterol extraction induced strong verotoxin binding in poorly reactive adult glomeruli, suggesting cholesterol can mask Gb(3) in glomerular lipid rafts. Binding of the human immunodeficiency virus (HIV) adhesin, gp120 (another Gb(3) ligand) was detergent sensitive, tubule-restricted, and inhibited by verotoxin B subunit pretreatment, and may relate to HIV nephropathy. Our study shows that differential membrane Gb(3) organization in glomeruli and tubules provides a basis for the age- and glomerular-restricted pathology of hemolytic uremic syndrome.
authors.affiliation: Division of Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Ontario, Canada.
authors.forename: Fahima
authors.initials: F
authors.lastname: Khan
authors.affiliation: Department of Pediatrics, Intensive Care Medicine, Sainte-Justine Hospital, University of Montreal, Ontario, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Proulx
authors.affiliation: Division of Molecular Structure and Function, Research Institute, The Hospital for Sick Children, Ontario, Canada; Department of Laboratory Medicine and Pathology, University of Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Ontario, Canada. Electronic address: cling@sickkids.ca.
authors.forename: Clifford A
authors.initials: CA
authors.lastname: Lingwood
mesh_terms: D000367:Age Factors; D000818:Animals; D002784:Cholesterol; D003902:Detergents / Q000494:pharmacology*; D015699:HIV Envelope Protein gp120 / Q000493:pharmacokinetics; D006463:Hemolytic-Uremic Syndrome / Q000473:pathology*; D006801:Humans; D007678:Kidney Glomerulus / Q000473:pathology*; D007684:Kidney Tubules / Q000473:pathology; D021962:Membrane Microdomains / Q000737:chemistry; D051379:Mice; D011485:Protein Binding; D011500:Protein Synthesis Inhibitors; D022603:Shiga Toxins / Q000493:pharmacokinetics*; D014281:Trihexosylceramides / Q000378:metabolism*
chemical_list: D003902:Detergents; D015699:HIV Envelope Protein gp120; D011500:Protein Synthesis Inhibitors; D022603:Shiga Toxins; D014281:Trihexosylceramides; C514793:gp120 protein, Human immunodeficiency virus 1; C018549:globotriaosylceramide; D002784:Cholesterol