title: 3,3'-Diindolylmethane attenuates LPS-mediated acute liver failure by regulating miRNAs to target IRAK4 and suppress Toll-like receptor signalling.
abstract: OBJECTIVE
  Acute liver failure (ALF) is a severe and potentially lethal clinical syndrome. 3,3'-Diindolylmethane (DIM) is a natural plant-derived compound with anti-cancer activities. Recently, DIM has also been shown to have anti-inflammatory properties. Here, we tested the hypothesis that DIM would suppress endotoxin-induced ALF.
  
  
  METHODS
  We investigated the therapeutic potential of DIM in a mouse model of D-galactosamine/Lipopolysaccharide (GalN/LPS)-induced ALF. The efficacy of DIM treatment was assessed by survival, liver histopathology, serum levels of alanine transaminase, pro-inflammatory cytokines and number of activated liver macrophages. Effects of DIM on the expression of two miRNAs, 106a and 20b, and their predicted target gene were measured by qRT-PCR and Western blotting. Effects of DIM on the release of TNF-α from RAW264.7 macrophages transfected with mimics of these miRNAs and activated by LPS was assessed by elisa.
  
  
  RESULTS
  DIM treatment protected mice from ALF symptoms and reduced the number of activated liver macrophages. DIM increased expression of miR-106a and miR-20b in liver mononuclear cells and decreased expression of their predicted target gene IL-1 receptor-associated kinase 4 (IRAK4), involved in signalling from Toll-like receptor 4 (TLR4). In vitro transfection of RAW264.7 cells using miRNA mimics of miR-106a and 20b decreased expression of IRAK4 and of TNF-α secretion, following LPS stimulation.
  
  
  CONCLUSIONS
  DIM attenuated GalN/LPS-induced ALF by regulating the expression of unique miRNAs that target key molecules in the TLR4 inflammatory pathway. DIM may represent a potential novel hepatoprotective agent.
authors.affiliation: Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, USA.
authors.forename: S
authors.initials: S
authors.lastname: Tomar
authors.forename: M
authors.initials: M
authors.lastname: Nagarkatti
authors.forename: P S
authors.initials: PS
authors.lastname: Nagarkatti
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D018932:Chemokine CCL2 / Q000097:blood; D005260:Female; D005688:Galactosamine; D007211:Indoles / Q000494:pharmacology / Q000627:therapeutic use*; D053592:Interleukin-1 Receptor-Associated Kinases / Q000378:metabolism; D015850:Interleukin-6 / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D008070:Lipopolysaccharides; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D017114:Liver Failure, Acute / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008262:Macrophage Activation / Q000187:drug effects; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism; D020011:Protective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015398:Signal Transduction / Q000187:drug effects; D051193:Toll-Like Receptors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D007211:Indoles; D015850:Interleukin-6; D008070:Lipopolysaccharides; D035683:MicroRNAs; D020011:Protective Agents; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; C577686:interleukin-6, mouse; D005688:Galactosamine; D000410:Alanine Transaminase; D053592:Interleukin-1 Receptor-Associated Kinases; C507774:Irak4 protein, mouse; D053148:Caspase 3; C016392:3,3'-diindolylmethane