title: Cell-permeable, small-molecule activators of the insulin-degrading enzyme.
abstract: The insulin-degrading enzyme (IDE) cleaves numerous small peptides, including biologically active hormones and disease-related peptides. The propensity of IDE to degrade neurotoxic Aβ peptides marks IDE as a potential therapeutic target for Alzheimer disease. Using a synthetic reporter based on the yeast a-factor mating pheromone precursor, which is cleaved by multiple IDE orthologs, we identified seven small molecules that stimulate rat IDE activity in vitro. Half-maximal activation of IDE by the compounds is observed in vitro in the range of 43 to 198 µM. All compounds decrease the K(m) of IDE. Four compounds activate IDE in the presence of the competing substrate insulin, which disproportionately inhibits IDE activity. Two compounds stimulate rat IDE activity in a cell-based assay, indicating that they are cell permeable. The compounds demonstrate specificity for rat IDE since they do not enhance the activities of IDE orthologs, including human IDE, and they appear specific for a-factor-based reporters since they do not enhance rat IDE-mediated cleavage of Aβ-based reporters. Our results suggest that IDE activators function in the context of specific enzyme-substrate pairs, indicating that the choice of substrate must be considered in addition to target validation in IDE activator screens.
authors: The University of Georgia, Athens, GA, USA.
authors: Sayali S
authors: SS
authors: Kukday
authors: Surya P
authors: SP
authors: Manandhar
authors: Marissa C
authors: MC
authors: Ludley
authors: Mary E
authors: ME
authors: Burriss
authors: Benjamin J
authors: BJ
authors: Alper
authors: Walter K
authors: WK
authors: Schmidt
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000493:pharmacokinetics / Q000494:pharmacology*; D057166:High-Throughput Screening Assays; D006801:Humans; D007339:Insulysin / Q000378:metabolism*; D007700:Kinetics; D000072235:Mating Factor; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D059748:Proteolysis; D051381:Rats; D054852:Small Molecule Libraries; D013379:Substrate Specificity; D015003:Yeasts / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: D020536:Enzyme Activators; D010455:Peptides; D054852:Small Molecule Libraries; D000072235:Mating Factor; D007339:Insulysin