Iguratimod, an allosteric inhibitor of macrophage migration inhibitory factor (MIF), prevents mortality and oxidative stress in a murine model of acetaminophen overdose

Mol Med. 2024 Mar 27;30(1):43. doi: 10.1186/s10020-024-00803-0.

Abstract

Background: Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that has been implicated in multiple inflammatory and non-inflammatory diseases, including liver injury induced by acetaminophen (APAP) overdose. Multiple small molecule inhibitors of MIF have been described, including the clinically available anti-rheumatic drug T-614 (iguratimod); however, this drug's mode of inhibition has not been fully investigated.

Methods: We conducted in vitro testing including kinetic analysis and protein crystallography to elucidate the interactions between MIF and T-614. We also performed in vivo experiments testing the efficacy of T-614 in a murine model of acetaminophen toxicity. We analyzed survival in lethal APAP overdose with and without T-614 and using two different dosing schedules of T-614. We also examined MIF and MIF inhibition effects on hepatic hydrogen peroxide (H2O2) as a surrogate of oxidative stress in non-lethal APAP overdose.

Results: Kinetic analysis was consistent with a non-competitive type of inhibition and an inhibition constant (Ki) value of 16 µM. Crystallographic analysis revealed that T-614 binds outside of the tautomerase active site of the MIF trimer, with only the mesyl group of the molecule entering the active site pocket. T-614 improved survival in lethal APAP overdose when given prophylactically, but this protection was not observed when the drug was administered late (6 h after APAP). T-614 also decreased hepatic hydrogen peroxide concentrations during non-lethal APAP overdose in a MIF-dependent fashion.

Conclusions: T-614 is an allosteric inhibitor of MIF that prevented death and decreased hepatic hydrogen peroxide concentrations when given prophylactically in a murine model of acetaminophen overdose. Further studies are needed to elucidate the mechanistic role of MIF in APAP toxicity.

Keywords: Acetaminophen; Drug discovery; Drug screening; Enzyme; Iguratimod; Inflammation; MIF; Toxicology.

MeSH terms

  • Acetaminophen / adverse effects
  • Animals
  • Benzopyrans*
  • Chemical and Drug Induced Liver Injury* / drug therapy
  • Chemical and Drug Induced Liver Injury* / metabolism
  • Chemical and Drug Induced Liver Injury* / prevention & control
  • Chromones*
  • Disease Models, Animal
  • Hydrogen Peroxide / metabolism
  • Kinetics
  • Liver / metabolism
  • Macrophage Migration-Inhibitory Factors*
  • Mice
  • Oxidative Stress
  • Sulfonamides*

Substances

  • Acetaminophen
  • T 614
  • Macrophage Migration-Inhibitory Factors
  • iguratimod
  • Hydrogen Peroxide
  • Benzopyrans
  • Chromones
  • Sulfonamides