title: Shiga toxin downregulates tissue factor pathway inhibitor, modulating an increase in the expression of functional tissue factor on endothelium.
abstract: BACKGROUND
  Endothelial expression of tissue factor (TF) may play a major role in (Stx)-related hemolytic uremic syndrome. We examined human umbilical vein endothelial cell (HUVEC) monolayers to determine the interaction between TF and TF pathway inhibitor (TFPI), hypothesizing that changes in TFPI modulate TF expression.
  
  
  METHODS
  We studied 1) cell surface expression of globotriasylceramide (Gb3, the receptor for Stx) with Stx-1 (10 pM), TNFα (20 Ng/ml), or Stx-1 plus TNFα compared to control, 2) gene expression of TF and TFPI, 3) total cellular and cell surface antigenic TF and TFPI, 4) TFPI secretion into supernatant, and 5) factor Xa production.
  
  
  CONCLUSIONS
  Gb3 expression, negligible with control and Stx-1 alone, increased significantly with TNFα and with Stx-1 plus TNFα. TF mRNA increased 1.25 ± 0.32- fold (N = 9; p = 0.041) with Stx-1 alone vs. 2.82 ± 0.92-fold (N = 13; p < 0.0005) with TNFα alone. However, Stx-1 plus TNFα yielded a 6.51 ± 3.48-fold increase (N = 17; p < 0.0005). TFPI mRNA decreased with TNFα (p < 0.001) and Stx-1 plus TNFα (p < 0.0005). Total cellular and cell surface TF antigen increased significantly with TNFα, but no further with Stx-1 plus TNFα. Total TFPI cellular and cell surface antigen levels, and TFPI secretion decreased significantly with Stx-1 plus TNFα. Median factor Xa production for Stx-1 plus TNFα vs TNFα alone increased (p < 0.001) 3.24-fold. Our results indicate that a subinhibitory concentration of Stx-1 plus TNFα impairs TFPI gene expression, synthesis, cell-surface association, and secretion, leading to augmented functional TF.
authors: Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. Grabowski.Eric@MGH.Harvard.edu
authors: Eric F
authors: EF
authors: Grabowski
authors: Rafail I
authors: RI
authors: Kushak
authors: Bohan
authors: B
authors: Liu
authors: Julie R
authors: JR
authors: Ingelfinger
mesh_terms: D015295:Antigens, Tumor-Associated, Carbohydrate / Q000235:genetics; D001777:Blood Coagulation; D005786:Gene Expression Regulation; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology; D054884:Host-Pathogen Interactions; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism / Q000382:microbiology*; D006801:Humans; D008074:Lipoproteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D022621:Shiga Toxin / Q000378:metabolism*; D012762:Shigella dysenteriae / Q000502:physiology; D015398:Signal Transduction; D013925:Thromboplastin / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; C472766:Gb3 antigen; D008074:Lipoproteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C051928:lipoprotein-associated coagulation inhibitor; D022621:Shiga Toxin; D013925:Thromboplastin