title: Shiga Toxin 2a-Induced Endothelial Injury in Hemolytic Uremic Syndrome: A Metabolomic Analysis.
abstract: BACKGROUND
  Endothelial dysfunction plays a pivotal role in the pathogenesis of postenteropathic hemolytic uremic syndrome (HUS), most commonly caused by Shiga toxin (Stx)-producing strains of Escherichia coli.
  
  
  METHODS
  To identify new treatment targets, we performed a metabolomic high-throughput screening to analyze the effect of Stx2a, the major Stx type associated with HUS, on human renal glomerular endothelial cells (HRGEC) and umbilical vein endothelial cells (HUVEC). Cells were treated either with sensitizing tumor necrosis factor α (TNF-α) or Stx2a, a sequence of both or remained untreated.
  
  
  RESULTS
  We identified 341 metabolites by combined liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry. Both cell lines exhibited distinct metabolic reaction profiles but shared elevated levels of free fatty acids. Stx2a predominantly altered the nicotinamide adenine dinucleotide (NAD) cofactor pathway and the inflammation-modulating eicosanoid pathway, which are associated with lipid metabolism. In HRGEC, Stx2a strongly diminished NAD derivatives, leading to depletion of the energy substrate acetyl coenzyme A and the antioxidant glutathione. HUVEC responded to TNF-α and Stx2a by increasing production of the counteracting eicosanoids prostaglandin I2, E1, E2, and A2, while in HRGEC only more prostaglandin I2 was detected.
  
  
  CONCLUSIONS
  We conclude that disruption of energy metabolism and depletion of glutathione contributes to Stx-induced injury of the renal endothelium and that the inflammatory response to Stx is highly cell-type specific.
authors.affiliation: Department of Pediatrics I, University Children's Hospital Heidelberg Division of Functional Genome Analysis, German Cancer Research Center.
authors.forename: Christian
authors.initials: C
authors.lastname: Betzen
authors.affiliation: Department of Pediatrics I, University Children's Hospital Heidelberg.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Plotnicki
authors.affiliation: Department of Pediatrics I, University Children's Hospital Heidelberg.
authors.forename: Farnoosh
authors.initials: F
authors.lastname: Fathalizadeh
authors.affiliation: Metabolon, Durham, North Carolina.
authors.forename: Kirk
authors.initials: K
authors.lastname: Pappan
authors.affiliation: Department of Medicine I and Clinical Chemistry, University Hospital Heidelberg.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fleming
authors.affiliation: Institute for Hygiene, University of Münster, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Bielaszewska
authors.affiliation: Institute for Hygiene, University of Münster, Germany.
authors.forename: Helge
authors.initials: H
authors.lastname: Karch
authors.affiliation: Department of Pediatrics I, University Children's Hospital Heidelberg.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Tönshoff
authors.affiliation: Department of Pediatrics I, University Children's Hospital Heidelberg.
authors.forename: Neysan
authors.initials: N
authors.lastname: Rafat
mesh_terms: D002478:Cells, Cultured; D015777:Eicosanoids / Q000235:genetics / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006463:Hemolytic-Uremic Syndrome / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D006801:Humans; D007678:Kidney Glomerulus / Q000166:cytology*; D055432:Metabolomics; D022641:Shiga Toxin 2 / Q000633:toxicity*
chemical_list: D015777:Eicosanoids; D022641:Shiga Toxin 2
keywords: Shiga toxin; endothelial cells; hemolytic uremic syndrome; metabolomics