title: Inhibitor of Apoptosis Protein-1 Regulates Tumor Necrosis Factor-Mediated Destruction of Intestinal Epithelial Cells.
abstract: Tumor necrosis factor (TNF) is a cytokine that promotes inflammation and contributes to pathogenesis of inflammatory bowel diseases. Unlike other cells and tissues, intestinal epithelial cells undergo rapid cell death upon exposure to TNF, by unclear mechanisms. We investigated the roles of inhibitor of apoptosis proteins (IAPs) in the regulation of TNF-induced cell death in the intestinal epithelium of mice and intestinal organoids.
  
  
  
  RNA from cell lines and tissues was analyzed by quantitative polymerase chain reaction, protein levels were analyzed by immunoblot assays. BIRC2 (also called cIAP1) was expressed upon induction from lentiviral vectors in young adult mouse colon (YAMC) cells. YAMC cells, the mouse colon carcinoma cell line MC38, the mouse macrophage cell line RAW 264.7, or mouse and human organoids were incubated with second mitochondrial activator of caspases (Smac)-mimetic compound LCL161 or recombinant TNF-like weak inducer of apoptosis (TNFSF12) along with TNF, and cell death was quantified. C57BL/6 mice with disruption of Xiap, Birc2 (encodes cIAP1), Birc3 (encodes cIAP2), Tnfrsf1a, or Tnfrsf1b (Tnfrsf1a and b encode TNF receptors) were injected with TNF or saline (control); liver and intestinal tissues were collected and analyzed for apoptosis induction by cleaved caspase 3 immunohistochemistry. We also measured levels of TNF and alanine aminotransferase in serum from mice.
  
  
  
  YAMC cells, and mouse and human intestinal organoids, died rapidly in response to TNF. YAMC and intestinal crypts expressed lower levels of XIAP, cIAP1, cIAP2, and cFLIP than liver tissue. Smac-mimetics reduced levels of cIAP1 and XIAP in MC38 and YAMC cells, and Smac-mimetics and TNF-related weak inducer of apoptosis increased TNF-induced cell death in YAMC cells and organoids-most likely by sequestering and degrading cIAP1. Injection of TNF greatly increased levels of cell death in intestinal tissue of cIAP1-null mice, compared with wild-type C57BL/6 mice, cIAP2-null mice, or XIAP-null mice. Excessive TNF-induced cell death in the intestinal epithelium was mediated TNF receptor 1.
  
  
  
  In a study of mouse and human cell lines, organoids, and tissues, we found cIAP1 to be required for regulation of TNF-induced intestinal epithelial cell death and survival. These findings have important implications for the pathogenesis of TNF-mediated enteropathies and chronic inflammatory diseases of the intestine.
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Grabinger
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: Konstantin J
authors.initials: KJ
authors.lastname: Bode
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Demgenski
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Seitz
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Delgado
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: Feodora
authors.initials: F
authors.lastname: Kostadinova
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany.
authors.forename: Cindy
authors.initials: C
authors.lastname: Reinhold
authors.affiliation: Cell Signaling and Cell Death Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Australia.
authors.forename: Nima
authors.initials: N
authors.lastname: Etemadi
authors.affiliation: Department of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Wilhelm
authors.affiliation: Department of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schweinlin
authors.affiliation: Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland.
authors.forename: Kay
authors.initials: K
authors.lastname: Hänggi
authors.affiliation: Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland.
authors.forename: Janin
authors.initials: J
authors.lastname: Knop
authors.affiliation: Department of Biology, University of Konstanz, Konstanz, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Hauck
authors.affiliation: Department of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg, Würzburg, Germany; Translational Center Würzburg, Würzburg branch of the Fraunhofer IGB, Würzburg, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Walles
authors.affiliation: Cell Signaling and Cell Death Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Silke
authors.affiliation: Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Wajant
authors.affiliation: Cell Signaling and Cell Death Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Australia.
authors.forename: Ueli
authors.initials: U
authors.lastname: Nachbur
authors.affiliation: Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland.
authors.forename: Wong
authors.initials: W
authors.lastname: W Wei-Lynn
authors.affiliation: Biochemical Pharmacology, Department of Biology, University of Konstanz, Germany. Electronic address: thomas.brunner@uni-konstanz.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Brunner
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D000074049:Cytokine TWEAK; D004847:Epithelial Cells / Q000187:drug effects; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics* / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects; D008099:Liver / Q000187:drug effects; D008264:Macrophages; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009940:Organoids; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000235:genetics; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000235:genetics; D013844:Thiazoles / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology; D048069:Tumor Necrosis Factors / Q000494:pharmacology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism*
chemical_list: C107521:Birc4 protein, mouse; D000074049:Cytokine TWEAK; D051034:Inhibitor of Apoptosis Proteins; C574246:LCL161; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; C109743:TNFSF12 protein, human; D013844:Thiazoles; C506236:Tnfrsf1a protein, mouse; C491645:Tnfsf12 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D048069:Tumor Necrosis Factors; C494833:BIRC2 protein, human; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; C494834:Birc2 protein, mouse; C494835:Birc3 protein, mouse; D044767:Ubiquitin-Protein Ligases
keywords: IBD; Mouse Model; TNF Signaling; TWEAK