Shiga toxin-2 triggers endothelial leukocyte adhesion and transmigration via NF-κB dependent up-regulation of IL-8 and MCP-1

Carla Zoja, Stefania Angioletti, Roberta Donadelli, Cristina Zanchi, Susanna Tomasoni, Elena Binda, Barbara Imberti, Maroeska Te Loo, Leo Monnens, Giuseppe Remuzzi, Marina Morigi

Research output: Contribution to journalArticle

Abstract

Background. Shiga toxin (Stx)-producing E. coli is a causative agent of the epidemic form of hemolytic uremic syndrome (HUS), the most common cause of acute renal failure in children. Endothelial injury and leukocyte activation are instrumental to the development of microangiopathic lesions. To obtain more insight into the mechanisms favoring endothelium-leukocyte interaction, we studied (1) the effect of Stx-2 on leukocyte adhesion and transmigration in human endothelial cells under flow; (2) the effect of Stx-2 on endothelial expression of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) and their functional role in the adhesive phenomena; and (3) the role of nuclear factor-κB (NF-κB) in endothelial chemokine expression. Methods. For adhesion experiments, human umbilical vein endothelial cells (HUVEC) and human glomerular endothelial cells (GEC) were incubated for 24 hours with Stx-2 (25 pmol/L), with or without anti-IL-8 or MCP-1 antibodies, and then exposed to leukocyte suspension under flow (1.5 dynes/cm2). IL-8 and MCP-1 expression was evaluated in Stx-2 treated endothelial cells (6 hours) by Northern blot. NF-κB activity was assessed by electrophoretic mobility shift assay. The role of NF-κB in Stx-induced chemokines was evaluated by transfecting HUVEC with an adenovirus coding for IκBα. Results. Stx-2 significantly enhanced the number of leukocytes that adhered and then migrated across the endothelium. Stx-2 increased the expression of IL-8 and MCP-1, which was preceded by NF-κB activation. Blocking of endothelial IL-8 and MCP-1 with corresponding antibodies significantly inhibited Stx-induced leukocyte adhesion and migration either in HUVEC or GEC. Adenovirus-mediated gene transfer of IκBα down-regulated IL-8 and MCP-1 mRNA and also inhibited the adhesion and transmigration of leukocytes in Stx-treated HUVEC. Conclusions. Stx-2 via a transcriptional activation mechanism specifically mediated by NF-κB up-regulates endothelial MCP-1 and IL-8. Both chemokines are important modulators of leukocyte adhesion and transmigration under flow. These findings might be relevant to understand the nature of microvascular lesions in HUS and open future perspectives for better treatment of microvascular thrombosis.

Original languageEnglish
Pages (from-to)846-856
Number of pages11
JournalKidney International
Volume62
Issue number3
DOIs
Publication statusPublished - 2002

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Keywords

  • Acute renal failure
  • Chemokines
  • Flow
  • Gene transfer
  • Glomerular endothelial cells
  • Hemolytic uremic syndrome
  • Thrombocytopenia

ASJC Scopus subject areas

  • Nephrology

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