title: Novel pharmacological chaperones that correct phenylketonuria in mice.
abstract: Phenylketonuria (PKU) is caused by inherited phenylalanine-hydroxylase (PAH) deficiency and, in many genotypes, it is associated with protein misfolding. The natural cofactor of PAH, tetrahydrobiopterin (BH(4)), can act as a pharmacological chaperone (PC) that rescues enzyme function. However, BH(4) shows limited efficacy in some PKU genotypes and its chemical synthesis is very costly. Taking an integrated drug discovery approach which has not been applied to this target before, we identified alternative PCs for the treatment of PKU. Shape-focused virtual screening of the National Cancer Institute's chemical library identified 84 candidate molecules with potential to bind to the active site of PAH. An in vitro evaluation of these yielded six compounds that restored the enzymatic activity of the unstable PAHV106A variant and increased its stability in cell-based assays against proteolytic degradation. During a 3-day treatment study, two compounds (benzylhydantoin and 6-amino-5-(benzylamino)-uracil) substantially improved the in vivo Phe oxidation and blood Phe concentrations of PKU mice (Pah(enu1)). Notably, benzylhydantoin was twice as effective as tetrahydrobiopterin. In conclusion, we identified two PCs with high in vivo efficacy that may be further developed into a more effective drug treatment of PKU.
authors.affiliation: Sections of Biochemical and Clinical Pharmacology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, 6020 Innsbruck, Austria.
authors.forename: Sandra
authors.initials: S
authors.lastname: Santos-Sierra
authors.forename: Johannes
authors.initials: J
authors.lastname: Kirchmair
authors.forename: Anna M
authors.initials: AM
authors.lastname: Perna
authors.forename: Dunja
authors.initials: D
authors.lastname: Reiss
authors.forename: Kristina
authors.initials: K
authors.lastname: Kemter
authors.forename: Wulf
authors.initials: W
authors.lastname: Röschinger
authors.forename: Hartmut
authors.initials: H
authors.lastname: Glossmann
authors.forename: Søren W
authors.initials: SW
authors.lastname: Gersting
authors.forename: Ania C
authors.initials: AC
authors.lastname: Muntau
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wolber
authors.forename: Florian B
authors.initials: FB
authors.lastname: Lagler
mesh_terms: D000818:Animals; D001665:Binding Sites; D001708:Biopterins / Q000031:analogs & derivatives / Q000378:metabolism; D020134:Catalytic Domain; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D055808:Drug Discovery; D004353:Drug Evaluation, Preclinical; D004795:Enzyme Stability; D006801:Humans; D006827:Hydantoins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology / Q000633:toxicity; D051379:Mice; D010084:Oxidation-Reduction; D010649:Phenylalanine / Q000378:metabolism; D010651:Phenylalanine Hydroxylase / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010661:Phenylketonurias / Q000188:drug therapy* / Q000378:metabolism; D017510:Protein Folding; D054852:Small Molecule Libraries; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity
chemical_list: C572752:6-amino-5-(benzylamino)uracil; D006827:Hydantoins; D054852:Small Molecule Libraries; D001708:Biopterins; C031427:5-benzylhydantoin; D010649:Phenylalanine; D014498:Uracil; D010651:Phenylalanine Hydroxylase; C003402:sapropterin