ABSTRACT
NF-κB-inducing kinase (NIK) mediates non-canonical NF-κB signaling downstream of multiple TNF family members, including BAFF, TWEAK, CD40, and OX40, which are implicated in the pathogenesis of systemic lupus erythematosus (SLE). Here, we show that experimental lupus in NZB/W F1 mice can be treated with a highly selective and potent NIK small molecule inhibitor. Both in vitro as well as in vivo, NIK inhibition recapitulates the pharmacological effects of BAFF blockade, which is clinically efficacious in SLE. Furthermore, NIK inhibition also affects T cell parameters in the spleen and proinflammatory gene expression in the kidney, which may be attributable to inhibition of OX40 and TWEAK signaling, respectively. As a consequence, NIK inhibition results in improved survival, reduced renal pathology, and lower proteinuria scores. Collectively, our data suggest that NIK inhibition is a potential therapeutic approach for SLE.
Subject(s)
B-Lymphocytes/drug effects , Kidney/drug effects , Lupus Erythematosus, Systemic/immunology , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , T-Lymphocytes/drug effects , Animals , B-Lymphocytes/immunology , Cell Proliferation/drug effects , Cell Survival/drug effects , Cytokine TWEAK/metabolism , Dendritic Cells/drug effects , Dendritic Cells/immunology , Disease Models, Animal , Gene Expression/drug effects , Humans , In Vitro Techniques , Inflammation/genetics , Interleukin-12 Subunit p40/drug effects , Interleukin-12 Subunit p40/immunology , Kidney/immunology , Kidney/pathology , Lupus Erythematosus, Systemic/drug therapy , Lupus Nephritis/immunology , Lupus Nephritis/pathology , Mice , Mice, Inbred NZB , Molecular Targeted Therapy , Proteinuria/immunology , Receptors, OX40/metabolism , Signal Transduction , Spleen/drug effects , Spleen/immunology , T-Lymphocytes/immunology , NF-kappaB-Inducing KinaseABSTRACT
Keap1 binds to the transcription factor Nrf2 and negatively modulates the expression of genes involved in cellular protection against oxidative stress. Small molecules have been discovered to inhibit the Nrf2:Keap1 interactions and act as antagonists of Keap1. The affinities of these small molecules are not very high and need further improvement in follow up hit-to-lead programs. In addition to the affinity parameters Ki, Kd, and IC50 thermodynamic parameters provide useful information for the selection and optimization of these hit molecules at the early stage of the lead discovery process. In this letter a tracer displacement assay was used to determine the thermodynamic signature of some of the known inhibitors of the Nrf2:Keap1 interaction. An optimized assay protocol is presented, which can be applied to other small molecules in hit-to-lead programs in a medium throughput manner.
