Allosteric inhibition of macrophage migration inhibitory factor revealed by ibudilast

Proc Natl Acad Sci U S A. 2010 Jun 22;107(25):11313-8. doi: 10.1073/pnas.1002716107. Epub 2010 Jun 8.


AV411 (ibudilast; 3-isobutyryl-2-isopropylpyrazolo-[1,5-a]pyridine) is an antiinflammatory drug that was initially developed for the treatment of bronchial asthma but which also has been used for cerebrovascular and ocular indications. It is a nonselective inhibitor of various phosphodiesterases (PDEs) and has varied antiinflammatory activity. More recently, AV411 has been studied as a possible therapeutic for the treatment of neuropathic pain and opioid withdrawal through its actions on glial cells. As described herein, the PDE inhibitor AV411 and its PDE-inhibition-compromised analog AV1013 inhibit the catalytic and chemotactic functions of the proinflammatory protein, macrophage migration inhibitory factor (MIF). Enzymatic analysis indicates that these compounds are noncompetitive inhibitors of the p-hydroxyphenylpyruvate (HPP) tautomerase activity of MIF and an allosteric binding site of AV411 and AV1013 is detected by NMR. The allosteric inhibition mechanism is further elucidated by X-ray crystallography based on the MIF/AV1013 binary and MIF/AV1013/HPP ternary complexes. In addition, our antibody experiments directed against MIF receptors indicate that CXCR2 is the major receptor for MIF-mediated chemotaxis of peripheral blood mononuclear cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Site
  • Binding Sites
  • Catalysis
  • Chemotaxis
  • Crystallography, X-Ray / methods
  • Cytokines / metabolism
  • Humans
  • Inflammation
  • Intramolecular Oxidoreductases / chemistry
  • Kinetics
  • Macrophage Migration-Inhibitory Factors / metabolism*
  • Phenylpyruvic Acids / chemistry
  • Platelet Aggregation Inhibitors / pharmacology
  • Protein Binding
  • Pyridines / chemistry*
  • Spectrometry, Fluorescence / methods


  • Cytokines
  • Macrophage Migration-Inhibitory Factors
  • Phenylpyruvic Acids
  • Platelet Aggregation Inhibitors
  • Pyridines
  • 4-hydroxyphenylpyruvic acid
  • Intramolecular Oxidoreductases
  • phenylpyruvate tautomerase
  • ibudilast

Associated data

  • PDB/3IJG
  • PDB/3IJJ