4-Pyridin-5-yl-2-(3,4,5-trimethoxyphenylamino)pyrimidines: potent and selective inhibitors of ZAP 70

Discovery and Structural Optimization of Covalent ZAP-70 Kinase Inhibitors against Psoriasis

Psoriasis is a chronic inflammatory skin disease closely related with T cells, and its management remains a challenge. Novel targets and associated drugs are urgently needed. Zeta-chain-associated protein kinase 70 kDa (ZAP-70) has been recognized as a potential target for treating autoimmune diseases due to its crucial role in T cell receptor signaling. In our previous work, we identified a potent and selective covalent ZAP-70 inhibitor with anti-inflammatory activity in vitro. Herein, we report the structural optimization of covalent ZAP-70 inhibitors. Our efforts led to the discovery of compound 25 (RDN2150), which exhibited potent inhibitory activity against ZAP-70 and favorable selectivity. It also demonstrated promising inhibitory effects on T cell activation and inflammatory cytokine production. Furthermore, a topical application of 25 resulted in significant efficacy in an imiquimod-induced psoriasis mouse model. Overall, these findings present the basis of a promising strategy for the treatment of psoriasis by targeting ZAP-70.

Discovery of a potent, selective, and covalent ZAP-70 kinase inhibitor

ZAP-70 (zeta-chain associated protein kinase 70 kDa) signaling pathway and its functions have been involved in the development and adaptive immune signaling of T cell. It thus represents a promising target for autoimmune diseases. Although reversible ZAP-70 kinase domain inhibitors have been developed, they are either weak or nonselective. We report herein the structure-guided development of the first potent and covalent inhibitor of ZAP-70 kinase domain. In particular, compound 18 (RDN009) showed good selectivity for ZAP-70 over structurally related Syk, and displayed potent inhibitory effects on T cell proliferation, activation, and inflammatory cytokine production. A mass spectrometry analysis further confirmed the covalent linkage between the inhibitor and ZAP-70 protein at C346. Overall, the covalent inhibitor RDN009 represents a potent and selective probe of ZAP-70 for further development for treatment of autoimmune diseases.

Designing of new multi-targeted inhibitors of spleen tyrosine kinase (Syk) and zeta-associated protein of 70kDa (ZAP-70) using hierarchical virtual screening protocol

In the present study, diverse inhibitor molecules of two protein tyrosine kinases i.e. Syk and ZAP-70 were considered for the pharmacophore and docking analyses to design new multi-targeted agents for these enzymes. These enzymes are non-receptor protein tyrosine kinases and both are expressed mainly in B and T-lymphocytes where they play a crucial role in immune signaling. The role of these two enzymes in inflammatory and autoimmune diseases makes them potential therapeutic targets for the designing of new multi-targeted agents to combat disease conditions associated with them. The pharmacophore models were developed for Syk and ZAP-70 inhibitors using PHASE module of Schrödinger software. The generated pharmacophore models for both enzymes were clustered and top five models for each target were selected on the basis of survival minus inactive score that were subsequently used for the 3D-QSAR analysis. The best model for Syk (ADHR.45-5) and ZAP-70 (AADRR.265-3) were selected corresponding to highest value of Q(2). Both models were employed for the screening of a PHASE database of approximately 1.5 million compounds, subsequently the retrieved hits were screened employing docking simulations with Syk and ZAP-70 proteins. Finally, the screened compounds having structural features of both pharmacophore models and displaying essential interactions with both proteins were investigated for ADME properties. Thus, the new leads obtained in this way would show inhibitory activity against Syk and ZAP-70, and may serve as novel therapeutic agents for the treatment of inflammatory disorders.

Structure-activity relationship studies of 5-benzylaminoimidazo[1,2-c]pyrimidine-8-carboxamide derivatives as potent, highly selective ZAP-70 kinase inhibitors

Zeta-associated protein, 70 kDa (ZAP-70), a spleen tyrosine kinase (Syk) family kinase, is normally expressed on T cells and natural killer cells and plays a crucial role in activation of the T cell immunoresponse. Thus, selective ZAP-70 inhibitors might be useful not only for treating autoimmune diseases, but also for suppressing organ transplant rejection. In our recent study on the synthesis of Syk family kinase inhibitors, we discovered that novel imidazo[1,2-c]pyrimidine-8-carboxamide derivatives possessed potent ZAP-70 inhibitory activity with good selectivity for ZAP-70 over other kinases. In particular, compound 26 showed excellent ZAP-70 kinase inhibition and high selectivity for ZAP-70 over structurally related Syk. The discovery of a potent, highly selective ZAP-70 inhibitor would contribute a new therapeutic tool for autoimmune diseases and organ transplant medication.

Discovery and design of benzimidazolone based inhibitors of p38 MAP kinase

A new class of benzimidazolone p38 MAP kinase inhibitors was discovered through high-throughput screening. X-ray crystallographic data of the lead molecule with p38 were used to design analogues with improved binding affinity and potency in a cell assay of LPS-induced TNFalpha production. Herein, we report the SAR of this new class of p38 inhibitors.