Identification and characterization of novel classes of macrophage migration inhibitory factor (MIF) inhibitors with distinct mechanisms of action.
Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, is considered an attractive therapeutic target in multiple inflammatory and autoimmune disorders. In addition to its known biologic activities, MIF can also function as a tautomerase. Several small molecules have been reported to be effective inhibitors of MIF tautomerase activity in vitro. Herein we employed a robust activity-based assay to identify different classes of novel inhibitors of the catalytic and biological activities of MIF. Several novel chemical classes of inhibitors of the catalytic activity of MIF with IC(50) values in the range of 0.2-15.5 microm were identified and validated. The interaction site and mechanism of action of these inhibitors were defined using structure-activity studies and a battery of biochemical and biophysical methods. MIF inhibitors emerging from these studies could be divided into three categories based on their mechanism of action: 1) molecules that covalently modify the catalytic site at the N-terminal proline residue, Pro(1); 2) a novel class of catalytic site inhibitors; and finally 3) molecules that disrupt the trimeric structure of MIF. Importantly, all inhibitors demonstrated total inhibition of MIF-mediated glucocorticoid overriding and AKT phosphorylation, whereas ebselen, a trimer-disrupting inhibitor, additionally acted as a potent hyperagonist in MIF-mediated chemotactic migration. The identification of biologically active compounds with known toxicity, pharmacokinetic properties, and biological activities in vivo should accelerate the development of clinically relevant MIF inhibitors. Furthermore, the diversity of chemical structures and mechanisms of action of our inhibitors makes them ideal mechanistic probes for elucidating the structure-function relationships of MIF and to further determine the role of the oligomerization state and catalytic activity of MIF in regulating the function(s) of MIF in health and disease.
Ouertatani-Sakouhi
Hajer
H
Laboratory of Molecular Neurobiology and Functional Neuroproteomics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
El-Turk
Farah
F
Fauvet
Bruno
B
Cho
Min-Kyu
MK
Pinar Karpinar
Damla
D
Le Roy
Didier
D
Dewor
Manfred
M
Roger
Thierry
T
Bernhagen
Jürgen
J
Calandra
Thierry
T
Zweckstetter
Markus
M
Lashuel
Hilal A
HA
D002633:Chemotaxis / Q000187:drug effects; D005938:Glucocorticoids; D006801:Humans; D020128:Inhibitory Concentration 50; D008263:Macrophage Migration-Inhibitory Factors / Q000037:antagonists & inhibitors* / Q000235:genetics; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship
D005938:Glucocorticoids; D008263:Macrophage Migration-Inhibitory Factors; D054852:Small Molecule Libraries; D051057:Proto-Oncogene Proteins c-akt