Improved lymphocyte function-associated antigen-1 (LFA-1) inhibition by statin derivatives: molecular basis determined by x-ray analysis and monitoring of LFA-1 conformational changes in vitro and ex vivo.
The integrin lymphocyte function-associated antigen-1 (LFA-1) (alphaLbeta2; CD11a/CD18) plays an important role in leukocyte migration and T cell activation. LFA-1 is inhibited by the cholesterol-lowering drug lovastatin, which binds to an allosteric site of the alphaL I domain termed the lovastatin site (L-site). Here we report for the first time the x-ray structures of the LFA-1 I domain complexed with derivatives of lovastatin optimized for LFA-1 inhibition. This analysis identified two new subpockets within the L-site occupied by chemical groups of the statin derivatives but not by lovastatin itself. Occupancy of these L-site subpockets led to distinct conformational changes in LFA-1, which were detectable by an epitope-monitoring assay. We utilized this assay to demonstrate improved LFA-1 inhibition in human blood in vitro and in blood samples from treated animals ex vivo. Moreover, we demonstrate that the novel lovastatin-derived LFA-1 inhibitor LFA878 exhibits potent anti-inflammatory effects in carrageenan-induced rat paw edema. In summary, the findings reported here extend the understanding of LFA-1 inhibition at the molecular level, allow for the identification and design of LFA-1 inhibitors of further enhanced potency, and support the expectation that LFA-1 inhibitors binding to the L-site will be of therapeutic value in treating inflammatory diseases.
Weitz-Schmidt
Gabriele
G
Novartis Institutes for BioMedical Research, CH-4002 Basel, Switzerland.
Welzenbach
Karl
K
Dawson
Janet
J
Kallen
Joerg
J
D000818:Animals; D001665:Binding Sites; D001769:Blood / Q000378:metabolism; D002351:Carrageenan / Q000494:pharmacology; D002465:Cell Movement; D004305:Dose-Response Relationship, Drug; D004487:Edema; D000939:Epitopes / Q000737:chemistry; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D019169:Jurkat Cells; D007962:Leukocytes / Q000166:cytology; D008148:Lovastatin / Q000494:pharmacology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008956:Models, Chemical; D008958:Models, Molecular; D009281:Naphthalenes / Q000737:chemistry* / Q000494:pharmacology*; D010078:Oxazines / Q000737:chemistry* / Q000494:pharmacology*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011817:Rabbits; D051381:Rats; D013601:T-Lymphocytes / Q000166:cytology; D013997:Time Factors; D014965:X-Rays
D000939:Epitopes; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; C494439:LFA 878; D016169:Lymphocyte Function-Associated Antigen-1; D009281:Naphthalenes; D010078:Oxazines; D002351:Carrageenan; D008148:Lovastatin