ABSTRACT
Increased fructose consumption and its subsequent metabolism have been implicated in metabolic disorders such as nonalcoholic fatty liver disease and steatohepatitis (NAFLD/NASH) and insulin resistance. Ketohexokinase (KHK) converts fructose to fructose-1-phosphate (F1P) in the first step of the metabolic cascade. Herein we report the discovery of a first-in-class KHK inhibitor, PF-06835919 (8), currently in phase 2 clinical trials. The discovery of 8 was built upon our originally reported, fragment-derived lead 1 and the recognition of an alternative, rotated binding mode upon changing the ribose-pocket binding moiety from a pyrrolidinyl to an azetidinyl ring system. This new binding mode enabled efficient exploration of the vector directed at the Arg-108 residue, leading to the identification of highly potent 3-azabicyclo[3.1.0]hexane acetic acid-based KHK inhibitors by combined use of parallel medicinal chemistry and structure-based drug design.
Subject(s)
Drug Discovery/methods , Enzyme Inhibitors/chemistry , Fructokinases/antagonists & inhibitors , Fructokinases/metabolism , Fructose/adverse effects , Metabolic Diseases/enzymology , Animals , Crystallography, X-Ray , Dogs , Dose-Response Relationship, Drug , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Fructose/administration & dosage , Hepatocytes/drug effects , Hepatocytes/enzymology , Humans , Insulin Resistance/physiology , Male , Metabolic Diseases/chemically induced , Metabolic Diseases/drug therapy , Protein Structure, Secondary , Rats , Rats, WistarABSTRACT
Increased fructose consumption and its subsequent metabolism have been implicated in hepatic steatosis, dyslipidemia, obesity, and insulin resistance in humans. Since ketohexokinase (KHK) is the principal enzyme responsible for fructose metabolism, identification of a selective KHK inhibitor may help to further elucidate the effect of KHK inhibition on these metabolic disorders. Until now, studies on KHK inhibition with small molecules have been limited due to the lack of viable in vivo pharmacological tools. Herein we report the discovery of 12, a selective KHK inhibitor with potency and properties suitable for evaluating KHK inhibition in rat models. Key structural features interacting with KHK were discovered through fragment-based screening and subsequent optimization using structure-based drug design, and parallel medicinal chemistry led to the identification of pyridine 12.
Subject(s)
Drug Design , Fructokinases/antagonists & inhibitors , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Animals , Crystallography, X-Ray , Fructokinases/chemistry , Fructokinases/metabolism , Humans , Male , Molecular Docking Simulation , Pyridines/chemistry , Pyridines/pharmacology , Rats , Rats, Sprague-DawleyABSTRACT
MAP KAP kinase 2 (MK2), a Ser/Thr kinase, plays a crucial role in the inflammatory process. We have determined the crystal structures of a catalytically active C-terminal deletion form of human MK2, residues 41-364, in complex with staurosporine at 2.7 A and with ADP at 3.2 A, revealing overall structural similarity with other Ser/Thr kinases. Kinetic analysis reveals that the K(m) for ATP is very similar for MK2 41-364 and p38-activated MK2 41-400. Conversely, the catalytic rate and binding for peptide substrate are dramatically reduced in MK2 41-364. However, phosphorylation of MK2 41-364 by p38 restores the V(max) and K(m) for peptide substrate to values comparable to those seen in p38-activated MK2 41-400, suggesting a mechanism for regulation of enzyme activity.
