ABSTRACT
While several therapeutic options exist, the need for more effective, safe, and convenient treatment for a variety of autoimmune diseases persists. Targeting the Janus tyrosine kinases (JAKs), which play essential roles in cell signaling responses and can contribute to aberrant immune function associated with disease, has emerged as a novel and attractive approach for the development of new autoimmune disease therapies. We screened our compound library against JAK3, a key signaling kinase in immune cells, and identified multiple scaffolds showing good inhibitory activity for this kinase. A particular scaffold of interest, the 1H-pyrrolo[2,3-b]pyridine series (7-azaindoles), was selected for further optimization in part on the basis of binding affinity (Ki) as well as on the basis of cellular potency. Optimization of this chemical series led to the identification of VX-509 (decernotinib), a novel, potent, and selective JAK3 inhibitor, which demonstrates good efficacy in vivo in the rat host versus graft model (HvG). On the basis of these findings, it appears that VX-509 offers potential for the treatment of a variety of autoimmune diseases.
Subject(s)
Autoimmune Diseases/drug therapy , Heterocyclic Compounds, 2-Ring/chemistry , Janus Kinase 3/antagonists & inhibitors , Valine/analogs & derivatives , Animals , Cell Line , Databases, Chemical , Dogs , Female , Graft vs Host Disease/drug therapy , Graft vs Host Disease/immunology , Haplorhini , Heterocyclic Compounds, 2-Ring/pharmacokinetics , Heterocyclic Compounds, 2-Ring/pharmacology , Humans , Janus Kinase 2/chemistry , Janus Kinase 3/chemistry , Male , Mice , Mice, Inbred BALB C , Mice, Inbred CBA , Microsomes, Liver/metabolism , Models, Molecular , Rats , Rats, Inbred Lew , Rats, Sprague-Dawley , Stereoisomerism , Structure-Activity Relationship , Valine/chemistry , Valine/pharmacokinetics , Valine/pharmacologyABSTRACT
Beyond their essential function as the building blocks of proteins, amino acids contribute to many aspects of plant biochemistry and physiology. Despite this, there are relatively large gaps in our understanding of the biochemical pathways and regulation of amino acid synthesis in plants. A rapid (1.5 min versus 20-90 min for standard methods) HPLC-MS/MS assay for separating 19 amino acids was developed for quantifying levels of free amino acids in plant tissue. This assay was used to determine the free amino acid content in the seeds of 10,000 randomly mutagenized Arabidopsis lines, and 322 Arabidopsis lines with increased levels of one or more amino acids were identified. The heritability of the mutant phenotype was confirmed for 43 lines with increased seed levels of the aspartate-derived amino acids Ile, Lys, Thr, or Met. Genetic mapping and DNA sequencing identified a mutation in an Arabidopsis threonine aldolase (AT1G08630, EC 4.1.2.5) as the cause of increased seed Thr levels in one mutant. The assay that was developed for this project has broad applicability to Arabidopsis and other plant species.
