The triterpenoid CDDO-imidazolide ameliorates mouse liver ischemia-reperfusion injury through activating the Nrf2/HO-1 pathway enhanced autophagy

Cell Death Dis. 2017 Aug 10;8(8):e2983. doi: 10.1038/cddis.2017.386.

Abstract

Nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated induction of antioxidants has been implicated to have protective roles in ischemia-reperfusion (I/R) injury in many animal models. However, the in vivo effects of CDDO-imidazole (CDDO-Im) (1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole), a Nrf2 activator, in hepatic I/R injury is lacking and its exact molecular mechanisms are still not very clear. The goals of this study were to determine whether CDDO-Im can prevent liver injury induced by I/R in the mouse, and to elucidate the molecular target of drug action. Mice were randomly equally divided into two groups and administered intraperitoneally with either DMSO control or CDDO-Im (2 mg/kg) 3 h before subjected to 90-min hepatic 70% ischemia followed by reperfusion. Subsequently, the Liver and blood samples of these mice were collected to evaluate liver injury. CDDO-Im pretreatment markedly improve hepatic I/R injury by attenuating hepatic necrosis and apoptosis, reducing reactive oxygen species (ROS) levels and inflammatory responses, and ameliorating mitochondrial dysfunction. Mechanistically, by using Nrf2 Knockout mice and hemeoxygenase 1 (HO-1) inhibitor, we found that these CDDO-Im protection effects are attributed to enhanced autophagy, which is mediated by activating Nrf2/HO-1 pathway. By accelerating autophagy and clearance of damaged mitochondria, CDDO-Im reduced the mtDNA release and ROS overproduction, and in turn decreased damage-associated molecular patterns induced inflammatory responses and the following secondary liver injury. These results indicate that by enhancing autophagy, CDDO-Im-mediated activation of Nrf2/HO-1 signaling could be a novel therapeutic strategy to minimize the adverse effects of hepatic I/R injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects
  • Blotting, Western
  • Cells, Cultured
  • DNA, Mitochondrial / genetics
  • Enzyme-Linked Immunosorbent Assay
  • Heme Oxygenase-1 / metabolism*
  • Hepatocytes / drug effects
  • Hepatocytes / metabolism
  • Imidazoles / therapeutic use*
  • In Situ Nick-End Labeling
  • Liver / drug effects
  • Liver / metabolism*
  • Liver Diseases / drug therapy
  • Liver Diseases / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microscopy, Electron, Transmission
  • NF-E2-Related Factor 2 / metabolism*
  • Oleanolic Acid / analogs & derivatives*
  • Oleanolic Acid / therapeutic use
  • RNA Interference
  • Reactive Oxygen Species / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects

Substances

  • 1-(2-cyano-3,12-dioxooleana-1,9-dien-28-oyl) imidazole
  • DNA, Mitochondrial
  • Imidazoles
  • NF-E2-Related Factor 2
  • Reactive Oxygen Species
  • Oleanolic Acid
  • Heme Oxygenase-1