Allosteric inhibition of macrophage migration inhibitory factor revealed by ibudilast.
Cho, Y., Crichlow, G.V., Vermeire, J.J., Leng, L., Du, X., Hodsdon, M.E., Bucala, R., Cappello, M., Gross, M., Gaeta, F., Johnson, K., Lolis, E.J.(2010) Proc Natl Acad Sci U S A 107: 11313-11318
- PubMed: 20534506 
- DOI: https://doi.org/10.1073/pnas.1002716107
- Primary Citation of Related Structures:  
3IJG, 3IJJ - PubMed Abstract: 
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.
Organizational Affiliation: 
Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510, USA.