title: Characterization of RA839, a Noncovalent Small Molecule Binder to Keap1 and Selective Activator of Nrf2 Signaling.
abstract: The activation of the transcription factor NF-E2-related factor 2 (Nrf2) maintains cellular homeostasis in response to oxidative stress by the regulation of multiple cytoprotective genes. Without stressors, the activity of Nrf2 is inhibited by its interaction with the Keap1 (kelch-like ECH-associated protein 1). Here, we describe (3S)-1-[4-[(2,3,5,6-tetramethylphenyl) sulfonylamino]-1-naphthyl]pyrrolidine-3-carboxylic acid (RA839), a small molecule that binds noncovalently to the Nrf2-interacting kelch domain of Keap1 with a Kd of ∼6 μM, as demonstrated by x-ray co-crystallization and isothermal titration calorimetry. Whole genome DNA arrays showed that at 10 μM RA839 significantly regulated 105 probe sets in bone marrow-derived macrophages. Canonical pathway mapping of these probe sets revealed an activation of pathways linked with Nrf2 signaling. These pathways were also activated after the activation of Nrf2 by the silencing of Keap1 expression. RA839 regulated only two genes in Nrf2 knock-out macrophages. Similar to the activation of Nrf2 by either silencing of Keap1 expression or by the reactive compound 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid methyl ester (CDDO-Me), RA839 prevented the induction of both inducible nitric-oxide synthase expression and nitric oxide release in response to lipopolysaccharides in macrophages. In mice, RA839 acutely induced Nrf2 target gene expression in liver. RA839 is a selective inhibitor of the Keap1/Nrf2 interaction and a useful tool compound to study the biology of Nrf2.
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Angelika F
authors.initials: AF
authors.lastname: Winkel
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Christian K
authors.initials: CK
authors.lastname: Engel
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Margerie
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany; Medical Faculty Mannheim, Heidelberg University, 69120 Mannheim, Germany.
authors.forename: Aimo
authors.initials: A
authors.lastname: Kannt
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Hauke
authors.initials: H
authors.lastname: Szillat
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Glombik
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kallus
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Ruf
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Güssregen
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Riedel
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany.
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Herling
authors.affiliation: Faculty of Medicine, Biochemistry I, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: von Knethen
authors.affiliation: Faculty of Medicine, Biochemistry I, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Weigert
authors.affiliation: Faculty of Medicine, Biochemistry I, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Brüne
authors.affiliation: R&D, Sanofi, 65926 Frankfurt, Germany. Electronic address: dieter.schmoll@sanofi.com.
authors.forename: Dieter
authors.initials: D
authors.lastname: Schmoll
mesh_terms: D000818:Animals; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D000072019:Kelch-Like ECH-Associated Protein 1; D008297:Male; D051379:Mice; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D011485:Protein Binding; D011759:Pyrrolidines / Q000378:metabolism / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D013449:Sulfonamides / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D011759:Pyrrolidines; C000606069:RA839 compound; D013449:Sulfonamides
keywords: diabetic nephropathy; drug discovery; gene expression; nuclear factor 2 (erythroid-derived 2-like factor) (NFE2L2) (Nrf2); oxidative stress; protein-protein interaction; signal transduction