ABSTRACT
The N-methyl-D-aspartate receptor (NMDAR) is a Na(+) and Ca(2+) permeable ionotropic glutamate receptor that is activated by the coagonists glycine and glutamate. NMDARs are critical to synaptic signaling and plasticity, and their dysfunction has been implicated in a number of neurological disorders, including schizophrenia, depression, and Alzheimer's disease. Herein we describe the discovery of potent GluN2A-selective NMDAR positive allosteric modulators (PAMs) starting from a high-throughput screening hit. Using structure-based design, we sought to increase potency at the GluN2A subtype, while improving selectivity against related α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). The structure-activity relationship of channel deactivation kinetics was studied using a combination of electrophysiology and protein crystallography. Effective incorporation of these strategies resulted in the discovery of GNE-0723 (46), a highly potent and brain penetrant GluN2A-selective NMDAR PAM suitable for in vivo characterization.
Subject(s)
Excitatory Amino Acid Antagonists/chemical synthesis , Excitatory Amino Acid Antagonists/pharmacology , Receptors, N-Methyl-D-Aspartate/drug effects , Animals , CHO Cells , Calcium/metabolism , Cricetinae , Cricetulus , Crystallography, X-Ray , Drug Discovery , HEK293 Cells , High-Throughput Screening Assays , Humans , Kinetics , Models, Molecular , Patch-Clamp Techniques , Receptors, AMPA/drug effects , Structure-Activity RelationshipABSTRACT
There is evidence that small molecule inhibitors of the non-receptor tyrosine kinase ITK, a component of the T-cell receptor signaling cascade, could represent a novel asthma therapeutic class. Moreover, given the expected chronic dosing regimen of any asthma treatment, highly selective as well as potent inhibitors would be strongly preferred in any potential therapeutic. Here we report hit-to-lead optimization of a series of indazoles that demonstrate sub-nanomolar inhibitory potency against ITK with strong cellular activity and good kinase selectivity. We also elucidate the binding mode of these inhibitors by solving the X-ray crystal structures of the complexes.
Subject(s)
Drug Discovery , Indazoles/pharmacology , Protein Kinase Inhibitors/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Crystallography, X-Ray , Dose-Response Relationship, Drug , Humans , Indazoles/chemical synthesis , Indazoles/chemistry , Jurkat Cells , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein-Tyrosine Kinases/metabolism , Structure-Activity RelationshipABSTRACT
The discovery of somatic Jak2 mutations in patients with chronic myeloproliferative neoplasms has led to significant interest in discovering selective Jak2 inhibitors for use in treating these disorders. A high-throughput screening effort identified the pyrazolo[1,5-a]pyrimidine scaffold as a potent inhibitor of Jak2. Optimization of lead compounds 7a-b and 8 in this chemical series for activity against Jak2, selectivity against other Jak family kinases, and good in vivo pharmacokinetic properties led to the discovery of 7j. In a SET2 xenograft model that is dependent on Jak2 for growth, 7j demonstrated a time-dependent knock-down of pSTAT5, a downstream target of Jak2.