ABSTRACT
All reported GnRH receptor mutants (causing human hypogonadotropic hypogonadism) are misfolded proteins that cannot traffic to the plasma membrane. Pharmacoperones correct misfolding and rescue mutants, routing them to the plasma membrane where they regain function. Because pharmacoperones are often peptidomimetic antagonists, these must be removed for receptor function after rescue; in vivo this necessitates pulsatile pharmacoperone administration. As an antecedent to in vivo studies, we determined whether pharmacoperones need to be present at the time of synthesis or whether previously misfolded proteins could be refolded and rescued. Accordingly, we blocked either protein synthesis or intra-cellular transport. Biochemical and morphological studies using 12 mutants and 10 pharmacoperones representing three different chemical classes show that previously synthesized mutant proteins, retained by the quality control system (QCS), are rescued by pharmacoperones, showing that pharmacoperone administration in vivo likely need not consider whether the target protein is being synthesized at the time of drug administration.
Subject(s)
Molecular Chaperones/pharmacology , Protein Folding , Protein Processing, Post-Translational/drug effects , Receptors, G-Protein-Coupled/metabolism , Receptors, LHRH/metabolism , Animals , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , COS Cells , Chlorocebus aethiops , Drug Evaluation, Preclinical , HeLa Cells , Humans , Indoles/pharmacology , Inositol/pharmacology , Molecular Mimicry , Mutant Proteins/chemistry , Mutant Proteins/genetics , Mutant Proteins/metabolism , Protein Transport/drug effects , Pyridines/pharmacology , Receptors, G-Protein-Coupled/chemistry , Receptors, G-Protein-Coupled/genetics , Receptors, LHRH/chemistry , Receptors, LHRH/genetics , TransfectionABSTRACT
A series of beta-aminoacylpiperidines bearing various fused five-membered heterocyclic rings was synthesized as dipeptidyl peptidase IV inhibitors. Potent and relatively selective inhibition could be obtained, depending on choice of heterocycle, regioisomerism, and substitution. In particular, one analog (74, DPP-IV IC50=26 nM) exhibited good oral bioavailability and acceptable half-life in the rat, albeit with rather high clearance.
Subject(s)
Dipeptidyl Peptidase 4/metabolism , Piperidines/chemical synthesis , Piperidines/pharmacology , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , Isoxazoles , Oxazoles , Piperidines/chemistry , Protease Inhibitors/chemistry , Pyrazoles , ThiazolesABSTRACT
A diastereoselective synthesis was used to prepare a series of (3-substituted-cyclopentyl and -cyclohexyl)glycine pyrrolidides and thiazolidides. The three chiral centers were generated in an unambiguous, stereochemically defined manner. Inhibitory activity was dependent on the configuration at each stereocenter and on the nature of the 3-substituent. In the cyclopentylglycine pyrrolidide series, high potency against dipeptidyl peptidase IV and good selectivity could be achieved.
