ABSTRACT
There is a critical need for safer and more convenient treatments for organ transplant rejection and autoimmune disorders such as rheumatoid arthritis. Janus tyrosine kinases (JAK1, JAK3) are expressed in lymphoid cells and are involved in the signaling of multiple cytokines important for various T cell functions. Blockade of the JAK1/JAK3-STAT pathway with a small molecule was anticipated to provide therapeutic immunosuppression/immunomodulation. The Pfizer compound library was screened against the catalytic domain of JAK3 resulting in the identification of a pyrrolopyrimidine-based series of inhibitors represented by CP-352,664 (2a). Synthetic analogues of 2a were screened against the JAK enzymes and evaluated in an IL-2 induced T cell blast proliferation assay. Select compounds were evaluated in rodent efficacy models of allograft rejection and destructive inflammatory arthritis. Optimization within this chemical series led to identification of CP-690,550 1, a potential first-in-class JAK inhibitor for treatment of autoimmune diseases and organ transplant rejection.
Subject(s)
Autoimmune Diseases/drug therapy , Graft Rejection/drug therapy , Janus Kinases/antagonists & inhibitors , Pyrimidines/chemical synthesis , Pyrroles/chemical synthesis , Animals , Blood Proteins/metabolism , Caco-2 Cells , Cell Line, Tumor , Cell Membrane Permeability , Cell Proliferation/drug effects , Cyclohexane Monoterpenes , Dogs , Female , Fibroblasts/cytology , Fibroblasts/drug effects , Humans , In Vitro Techniques , Lymphocyte Activation/drug effects , Macaca fascicularis , Male , Models, Molecular , Monoterpenes/chemical synthesis , Monoterpenes/pharmacokinetics , Monoterpenes/pharmacology , Piperidines/chemical synthesis , Piperidines/pharmacokinetics , Piperidines/pharmacology , Protein Binding , Pyrimidines/pharmacokinetics , Pyrimidines/pharmacology , Pyrroles/pharmacokinetics , Pyrroles/pharmacology , Rats , Rats, Sprague-Dawley , Stereoisomerism , Structure-Activity Relationship , T-Lymphocytes/cytology , T-Lymphocytes/drug effects , T-Lymphocytes/immunology , Tissue DistributionABSTRACT
OBJECTIVE: The CCR2 receptor plays a crucial role in monocyte recruitment and has been implicated as a contributing factor to atherosclerosis. CCR2 receptor deletion leads to significant inhibition of lesion development. Our objective was to determine if CCR2 receptor blockade with a small molecule would have a beneficial effect of decreasing established lesions. METHODS AND RESULTS: We demonstrated that CCR2 blockade had no significant effect on advanced lesions or the progression of fatty streaks. CCR2 blockade in mice resulted in elevations in plasma CCL2 levels and a significant reduction in the plasma Ly-6C(hi) subpopulations of monocytes expressing the CCR2 receptor. Neither CCL2 elevation nor margination of the Ly-6C(hi) population was observed in CCR2(-/-) mice. CONCLUSIONS: CCR2 receptor blockade with a small molecule antagonist at dose levels showing efficacy in several inflammatory models did not show a beneficial effect in murine models of atherosclerosis. Elevations in CCL2 and margination of Ly-6C(hi) cells demonstrate that the role of CCR2 in controlling monocyte levels goes beyond the control of monocyte emigration.
Subject(s)
Apolipoproteins E/genetics , Atherosclerosis/genetics , Atherosclerosis/metabolism , Monocytes/metabolism , Receptors, CCR2/antagonists & inhibitors , Animals , Antigens, Ly/metabolism , Aortic Valve/metabolism , Bone Marrow Transplantation , Chemokine CCL2/metabolism , Macaca fascicularis , Macrophages/metabolism , Male , Mice , Mice, Transgenic , Models, BiologicalABSTRACT
Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings.
