title: Shiga toxin promotes podocyte injury in experimental hemolytic uremic syndrome via activation of the alternative pathway of complement.
abstract: Shiga toxin (Stx)-producing Escherichia coli is the offending agent of postdiarrhea-associated hemolytic uremic syndrome (HUS), a disorder of glomerular ischemic damage and widespread microvascular thrombosis. We previously documented that Stx induces glomerular complement activation, generating C3a responsible for microvascular thrombosis in experimental HUS. Here, we show that the presence of C3 deposits on podocytes is associated with podocyte damage and loss in HUS mice generated by the coinjection of Stx2 and LPS. Because podocyte adhesion to the glomerular basement membrane is mediated by integrins, the relevance of integrin-linked kinase (ILK) signals in podocyte dysfunction was evaluated. Podocyte expression of ILK increased after the injection of Stx2/LPS and preceded the upregulation of Snail and downregulation of nephrin and α-actinin-4. Factor B deficiency or pretreatment with an inhibitory antibody to factor B protected mice against Stx2/LPS-induced podocyte dysregulation. Similarly, pretreatment with a C3a receptor antagonist limited podocyte loss and changes in ILK, Snail, and α-actinin-4 expression. In cultured podocytes, treatment with C3a reduced α-actinin-4 expression and promoted ILK-dependent nuclear expression of Snail and cell motility. These results suggest that Stx-induced activation of the alternative pathway of complement and generation of C3a promotes ILK signaling, leading to podocyte dysfunction and loss in Stx-HUS.
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Monica
authors.initials: M
authors.lastname: Locatelli
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Simona
authors.initials: S
authors.lastname: Buelli
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Anna
authors.initials: A
authors.lastname: Pezzotta
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Daniela
authors.initials: D
authors.lastname: Corna
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Luca
authors.initials: L
authors.lastname: Perico
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Susanna
authors.initials: S
authors.lastname: Tomasoni
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Daniela
authors.initials: D
authors.lastname: Rottoli
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Paola
authors.initials: P
authors.lastname: Rizzo
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Debora
authors.initials: D
authors.lastname: Conti
authors.affiliation: Division of Nephrology and Hypertension, University of Colorado Denver School of Medicine, Aurora, Colorado; and.
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Thurman
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy; Unit of Nephrology and Dialysis, Azienda Ospedaliera Papa Giovanni XXIII, Bergamo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Remuzzi
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy;
authors.forename: Carlamaria
authors.initials: C
authors.lastname: Zoja
authors.affiliation: IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri," Centro Anna Maria Astori, Bergamo, Italy; marina.morigi@marionegri.it.
authors.forename: Marina
authors.initials: M
authors.lastname: Morigi
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D015926:Complement C3a / Q000378:metabolism*; D003170:Complement Pathway, Alternative / Q000187:drug effects*; D004195:Disease Models, Animal; D006463:Hemolytic-Uremic Syndrome / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007678:Kidney Glomerulus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D050199:Podocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D022641:Shiga Toxin 2 / Q000494:pharmacology*; D015398:Signal Transduction; D000099200:Scaffold Protein ILK
chemical_list: D015926:Complement C3a; D008070:Lipopolysaccharides; D017346:Protein Serine-Threonine Kinases; D022641:Shiga Toxin 2; D000099200:Scaffold Protein ILK
keywords: acute renal failure; complement; hemolytic uremic syndrome; podocyte